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What is a prefix? — an introduction


On our parent page, we went over the term, affixation, which is the process of adding a prefix or suffix to a root word to change it. Now, we are going to focus solely on the prefix for this section.

Prefixes by definition are morphemes (the smallest possible unit with grammatical functionality — these are your atoms!) that are added onto the beginning of root words to alter their meaning.

For example, dis is one of many such prefixes. Dis has the sense of “opposite of” or “against”.

Let’s take a look at the prefix dis, as an example, to see how many types of words can be made.


Disagree.I disagree with your proposal.
Disappear.She just disappeared.
Disintegrate.It seems the world is disintegrating.
Disapprove.I disapprove of your behaviour. 


Disagreement.I hate disagreements.
Disappearance.There’s been a disappearance.
Disintegration.We’re seeing a disintegration.
Disapproval.There was disapproval from the passers-by.


Disagreed.The disagreed price.
Disappeared.A disappeared island.
Disintegrated.It’s a disintegrated company.
Disapproving.He received disapproving looks.


Note that most past participles “surprised”, “changed” etc., also function as adjectives. Moreover, gerund forms such as “surprising”, “changing” etc., also function as adjectives. This is just a small example of how many words you can create and utilise just by knowing one affix (in this case, it’s a suffix –ing).

The list of prefixes is long, and we’re not going to go over all of the prefixes in this course. Nevertheless, what we will do is teach you how to utilise different prefixes depending on what kind of word you want to use, i.e., an adverb, noun, adjective, verb etc.

By just knowing 1 prefix, you can create many new words

Let’s analyse how you can use the same prefix for the same word to create many more words.

To start, we will use a handful of popular prefixes that are primarily used for negation, that is, for making phrases negative, –il, –im, –in, –un and –ir.

Noun = illegality.There is far too much illegality to what you’re saying.
Verb = illegalise (UK spelling) / illegalize (US spelling)In some countries, they have illegalised smoking in bars.
Adverb = illegally.You have been working illegally.
Adjective = illegal.This is completely illegal.

—im: possible

Noun = impossibilityThere are too many impossibilities for my liking I’m afraid.
Adverb = impossiblyImpossibly, he manages to climb the mountain.
Adjective = impossibleThis is surely an impossible task.

—in: definite

Noun = IndefinitenessThere is just a lot of indefiniteness in this project.
Adverb = IndefinitelyWe’ll be living here indefinitely.
Adjective = IndefiniteThe subject is indefinite.

—un: forgive

Noun = unforgiveness and unforgiverLeave your unforgiveness behind you. We are unforgivers.
Verb = unforgiveHe unforgave me, unfortunately.
Adverb = unforgivinglyThey unforgivingly stole everything.
Adjective = unforgivableThis crime is unforgivable.

 —ir: responsible

Noun = irresponsibilityJack’s irresponsibility led us here.
Verb = irresponsibilise (UK spelling) / irresponsibilize (US spelling) (rare)You’ve managed to irresponsiblise our duties, thanks (sarcastically).
Adverb = irresponsiblySometimes you seem to behave irresponsibly.
Adjective = irresponsible.That’s an irresponsible excuse.

The prefixes that we have used are for negation usage, that is, to make words negative. Follow along, and we will focus on other prefixes and how to use them.

As you can see from the tables above, the prefixes do not normally change the category of a word, rather, this is the task of suffixes, that is, to alter part of speech. For instance, adjective to an adverb, or noun to a negative noun etc.

Which prefix do I use?

How do we know which prefix to use? Is there a rule for correct prefix utilisation, or affix utilisation in general? Unfortunately, there is no rule as to which affix goes where, however, once you know the intended purpose of each prefix (or suffix) it’s easy to add them.

Once you know, for example, the prefix en means “cause to be” or “put into” you can then apply these prefixes to a plethora of verbs, thereby increasing your vocabulary and overall proficiency in English.

These are just a couple of examples, but let’s take a look.

Many common words such as able, slave, trust, rich, courage, dear, close, and circle can be turned into verbs just by using –en. (In this case, the prefix, –en does indeed change the category of the word).

As an example, let’s use the prefix –en to make verbs

Common words (adjectives and nouns)VerbContext
AbleEnableYou’ve enabled me to do anything that I want.
SlaveEnslaveMany were enslaved.
TrustEntrustI have entrusted upon you my throne.
RichEnrichThis experience will surely enrich you.
CourageEncourageLet’s encourage her so she can join in.  
DearEndearYou have certainly endeared me to do my best.
CloseEncloseWe have enclosed something for you in the letter.
CircleEncircleYou’ll need to encircle the town.

How to know which prefix to use if there’s more than one

But how can we know which prefix to use if there is, on occasion, more than one option?

Correct prefix utilisation is not easy, however, by knowing each prefix’s rule, your language learning experience shall be immediately improved.

The key to this lesson is showing you, the learner, the mechanics of prefix usage and how to apply prefixes to the words you use in English.

If you’ve already been learning English for some time, some prefixes (and suffixes) will just sound more natural to you than others, and generally, this means that the more natural-sounding prefix is usually the correct option.

We’re not saying you’ll select the correct prefix every single time based on this logic, but you will get most of them right. Let’s take a quick look.

Prefix rules — an example

Take for instance the prefix sub which means “above” and “under”. Which other prefixes can you think of that have a similar meaning? Not many, well, maybe un, but we use this prefix for negation and not for the above reasons.

Nevertheless, let’s go through some newly made words with the prefix sub to see which is the best.

Let’s take the words, merge, marine, category, continent, way, contractor; what sounds more natural to you:

I hope you said, submerge, submarine and subcontractor.

These options should sound like the best options for any English learner that has been submerged in the language for at least six months.

On the other hand, correct utilisation of prefixes is easier than correct utilisation of suffixes simply because there are more options when it comes to suffixes, but that is a topic for our next lesson on suffixes.

What kinds of words (noun, adjective etc.) can a prefix make?

All this talk about prefixes, but what kinds of words do prefixes make?

Generally, prefixes don’t determine the class of a word, i.e., a noun, verb, adjective, adverb etc., that’s the principal job for suffixes (suffixes will be discussed in the next lesson).

So, for a word to change the form, i.e., to a verb or to an adjective etc., a new suffix needs to be added.

Nevertheless, let’s take a look at a few words that are using the same prefix throughout all the different forms so that you can see how one word can change into different words whilst the prefix stays the same.

A very popular prefix –inter is used to mean “between”. We’ll take a look at some words in different forms.

Example word: change

InterchangeabilityCapable of being changed (in nominal form).There is some serious interchangeability in times of financial crisis.
InterchangeThe act of interchanging (in nominal form).At our school we get to do interchanges between countries.
InterchangeThe act of interchanging (in verbal form).We have interchanged ideas and it feels amazing.
Interchangeable InterchangingThe act of interchanging (in adjectival form).My trousers are interchangeable. An interchanging process.
InterchangeablyThe act of interchanging (in adverbial form).We moved interchangeably on the dance floor.

The same prefix (-inter) was used to mean “between”, and it was used with different forms (nouns, a verb, adjectives, and an adverb).

The prefix per se didn’t alter the words (the suffixes altered the words), but this short example has shown that you can use the same prefix to make different types of words whilst using the same stem.

Ultimately, this makes your job easier, and eventually, your English will become much more concise and articulate.

Cursos de Inglés — Método Divertido

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