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Prefixes: How Can They Help You Improve Your English?

Rachael likes to share what she has learned through her blogging experience with new bloggers.

I hope you will NOT find this article unhelpful!

I hope you will NOT find this article unhelpful!

What Is a Prefix?

A prefix is just part of a word that is attached to the beginning of it, and a suffix is something attached to the end of a word. They're often keys to understanding the meaning of a word.

However, it's not always easy to get the meaning of a word this way. Sometimes, a prefix or suffix can have multiple meanings. So some words have meanings you would not expect based on what the prefix or suffix normally means.

1. In-: Three Different Meanings?

The biggest example is the prefix in-. This prefix usually means "not."

For example:

  • "Independent" means "not dependent."
  • "Indecent" means "not decent."
  • "Ineffective" means "not effective," and so on.

But sometimes, it can mean "very." This is the case with the etymology (word origin) of words like "inflammable," "incandescent," and "invaluable."

In- can also mean "in," as in, "inside." For example, the word "intuition" comes from the Latin word "in" as in "into" and "tueri," "to look, watch, guard, see, observe." So "intuition" comes from a word meaning "to look into." "Input" and "invest" use this kind of the "in-" prefix.

It's confusing, but as you build up your vocabulary, you will notice which words mean in as in "into," "not," or "very."

Before a word with a "p" or "b," "in-" becomes "im-." That's why we have "impossible," "important," "impotent," "imperfect," "imbecile," and so on. It's a rule also followed in Romance languages. So thanks, weird ancient Latin rules?

2. Pre- and Post-: Time-Based Prefixes

These are easier to understand.

Pre- means "before," and post- means "after." "After" itself is sometimes used as a prefix, as in "afternoon" and "aftermath." But for some reason, "before" is almost never used as a suffix.

Common words with "pre-" and "post-":

  • Premature
  • Prefabricated (means already made)
  • Prepaid (means you paid for it up front, as opposed to receiving a monthly bill)
  • Prepare
  • Post-industrial
  • Posthaste (fancy way of saying "extreme speed is needed")
  • Postpone - means to put something off until later

Note that "post" also has a meaning as a noun. It refers to something stuck in the ground that is vertical, like a "fence post" or "light post." If a post is big around enough, it gets designated a "pole," as in a "telephone pole," which is a big pole used to support cable and phone wires.

A 'post' is also any job that is seen as strict and ties a person to one spot during their entire shift. Or it can mean a military assignment.

The concept of an "internet post" or "posting" as a verb comes from the idea that people used to put notices and signs on physical posts outside. "Posting" also meant putting signs or pamphlets on something that isn't a post, such as a wall or bulletin board. For example, Martin Luther "posted" his 95 theses onto the church in Wittenberg.

  • Post-apocalyptic is a genre of fiction having to do with events after a major catastrophe that destroyed most of the world.
  • Pre-natal refers to everything before a baby is born, so it means something to do with pregnancy or the care of pregnant women (ex., prenatal vitamins, prenatal health checkups).
  • Posterior is used to mean 'behind' in anatomy, due to the use of Latin-rooted words in the field for scientific precision. Therefore, it's also a slightly odd-sounding slang for a person's butt.
  • Ante- is a Latin root prefix that means "before" or "front," and can also mean "past." So an antechamber is a room in the front of a building. An "antique" is something from before today (the past). This prefix isn't used much, and what's more common is the prefix anti- which means contrary to, against, or opposite of something.

3. Negation Prefixes: Un-, Dis-, Non-, Anti-, etc.

Many prefixes can be used that mean "not" something. The problem is knowing which one is correct. For example, there's this joke in The Simpsons when simple kid Martin says, "Me fail English? That's unpossible!" Which is funny because it contains three English errors. It should be "I" because "me" is an object pronoun rather than a subject pronoun. The tense of the verb 'fail' should be changed to 'failed' (past action) or maybe 'am failing' (continuous action). Third and finally, it's "impossible." Not "unpossible," which is not a word.

One thing I think is funny about English is that we have many negation prefixes.


  • Dis- as in: discord, discourteous, disappoint, disrepair, disgruntled
  • Des- for words with a "p," like despair and desperate
  • Dys- less common, used in "dysfunctional." It's not a negation like "dis," coming from a Greek root for "bad." So "dysfunctional" doesn't just mean "not functional," but "badly functional." This prefix is used in a lot of medical terms (you can find a list of words prefixed with "dys-" here.
  • Anti- not mere negation, but actively against something, for example, antioxidants are things that fight oxidation.
  • Un- a common negation prefix: unstoppable, unequivocal, unimportant, uncertain, untrue, untested, uninterested, unreliable, unimpressive. Usually, "un-" is used if the word the prefix modifies starts with a vowel.
  • Con- similar to "anti-," in words like: contrary, contest, contempt, contrast, changed to "com-" for "p" words like with "compete" and "compare."
  • De- similar to "dis-," it usually applies to actions, like "decentralize," "deprogram," and "decode." It means to undo the action.

Forming an adjective by using the past tense of these means something that has gone through that process, e.g., a "decentralized government." "Determined" comes from de- plus a Latin root 'terminate' meaning 'stop'. So it comes from a meaning of "not intending to stop."

"De-" also has multiple meanings. It can be an intensifier, like in the case of "defraud," which means to commit a fraud. It can also mean to separate something off something else, like "deform" or "defenestration." "Defense" comes from the Latin root to mean "to fight/hit back." So the "de-" in this sense means something being returned or reciprocated.

Confusingly though, some "con" and "com" words also have a different meaning. With, or joining together. This is the meaning of the roots of "congress," "composition," and "companion." Nutty.

Then there is the use of in- as a negation prefix, but in- does not always mean negation, as discussed above.

  • Non- is usually used more often in scientific, technical, and psychological terms. It's almost always, but not always, hyphenated. For example; non-alcoholic, non-ionic, non-compliant, non-essential, nonchalant, nonplussed.

Note that when you want to do a negation and aren't sure how, it's usually fine to just say "not X". For example, you can say "he was not impressed". That's a perfectly acceptable way to communicate. Also, many adjectives cannot be modified with a negation prefix. We don't say "ungood," "nonpretty," or "inblue." In other languages, you can use negation prefixes on any noun, adjective, or adverb. Not so in English.

In English, the most common way to do negation is with the addition of the word 'not. The word "not" is usually used immediately before the thing it modifies. For example, it's "I was not there that day," but never "I was there not that day." In Shakespearean English, interestingly, this was reversed, and English followed a French pattern by putting "not" after the thing it modified. So doing that can be seen as archaic and poetic, for example, the flower 'forget me not', or the game girls play of "he loves me/he loves me not." It's OK to do this in literature and especially poetry, but it is not standard usage.

4. En- and Em-

En- can be used in a few different ways, including to mean inside, but in most cases it means to cover, and can also be an intensifier. Before an 'm', 'p', or 'b', it becomes 'em-'.

Word examples:

  • Embargo: A ban on something, or an attempt to totally block commerce to a place (often by blocking sea trade).
  • Empire: An expansive political body controlling many smaller groups, regions, or nations.
  • Empathy: Comes from "en" meaning "inside" and "pathia" meaning 'feeling/passion'. It means feeling strong feelings someone else is feeling. 'Sympathy' is often used interchangeably, but it has a weaker meaning (source).
  • Ensnare: To trap.
  • Enable:To make someone or something able.
  • Empower: To give power to do something to someone, or to cause them to feel powerful.
  • Employ: Means to use, or to put to work.
  • Embrace: To hug, hold, or display physical affection in some way.
  • Enter: To go inside a building or home.
  • Enjoy: To get joy from something.
  • Encircle: To surround something or someone, forming a circle around it. But to merely draw a circle around something on paper is just called "circling."
  • Encryption: Putting something into code. "Decryption" means taking it out of code again.

It's interesting how some in of these words, the "em-" or "en-" means "into," or "inside," but other times, it means "cover" or "surround."

Finishing Up

A lot of English words are constructed with prefixes. In this article, I discuss a few of the more common types of prefixes, with a focus on the ones that are more tricky or confusing, because they can sometimes have multiple meanings. Brushing up on Greek and Latin roots is not exactly a thrill ride, but it is a critical, or important, part of understanding the language. When you develop a good understanding of prefixes and suffixes, you will become better at guessing what a word means that you don't know.

For example, the longest word in the dictionary was once "antidisestablishmentarianism." This word can be broken up into prefixes, a root word, and suffixes, as such:

  • Anti- against
  • dis- not
  • establishment -the idea (in this historical context) of retaining an established official religion in England
  • -arian part of a group believing in
  • -ism an idea, principle, or philosophy.

So from that, we can piece together that that super-scary, long word means something like 'a group against the idea of not keeping the established church'. Which is a double negative, and it's not general practice in English to use multiple prefixes and suffixes in the same word. A better word would simply be "pro-establishment." So this word is a bit weird and outdated. But you get the idea of how one can dissect certain words and understand them better, if you know the meanings of the prefixes, roots, and suffixes, even if you've never seen that particular word before.

Well, happy studying!

Please note: I realize this is not a complete list of prefixes. I plan on doing more like this, and I also plan on talking about suffixes and root words, provided this kind of article is reasonably well-received.


Peggy Woods from Houston, Texas on May 11, 2018:

This is a good article particularly for people trying to become proficient in the use and understanding of the English language.