The en- in enemy is a prefix meaning "not": the origin is Latin inimicus, from in- + amicus — a "not friend" or an "unfriend" (Online Etymology Dictionary—enemy).

The Latin in- changed to en- when the word passed through French and into English. Compare enmity, which keeps the en- form, and inimical, which is the same origin, but uses in-. I assume the difference here is the difference in their relative dates of entry into English. The Online Etymology Dictionary dates enemy to early 13c. and inimical to the 1640s.

In the entry for in-, the Online Etymology Dictionary notes:

In Old French and Middle English often en-, but most of these forms have not survived in Modern English, and the few that do (enemy, for instance) no longer are felt as negative. The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.

By "these forms have not survived", does this mean the prefixes were changed to in-, or have these words disappeared altogether? Why did this change occur? Are there any other examples of the en- form surviving as a negative prefix besides enemy and enmity?

  • The only other example I can think of is envy.
    – deadrat
    Commented Mar 29, 2016 at 5:05
  • @deadrat: That's from the other in- prefix.
    – herisson
    Commented May 29, 2016 at 6:40
  • @sumelic I stand corrected.
    – deadrat
    Commented May 29, 2016 at 6:47

2 Answers 2


Short answer: entire.

Long answer:

The two Latin prefixes in-: negative and prepositional

There are two Latin prefixes that have the same form in- (or im- before p,b, or m; ir- before r, and il- before l). One of them has a negative meaning (it is cognate to and has a similar meaning to the English negative prefix un-). Examples of words with this suffix: invalid, immature, irrelevant, illiterate. The other has a vague but generally prepositional meaning, as it was derived from the Latin preposition in (which is cognate to and has a similar meaning to the English preposition in). Examples of words with this suffix: incident, impulse, irritate, illustrate.

There are many words in English that start with en- or em- derived from the Latin prepositional prefix in- (such as envy, endure and embrace).

However, your question is about the negative prefix in particular.

Development in French of the Latin negative prefix in-

The change of Latin in- to French en- is in accordance with the regular sound change of Latin short /i/ to Proto Western Romance /e/ (shown in a table on this Wikipedia page). However, it seems that in general, the negative prefix en- ended up being replaced by in- (in both French and English). As your quote says, in general, the negative meaning of en- is not obvious in the words that retained the prefix. I found a description of this change with some examples here: Principles of English Etymology: The foreign element, by Walter William Skeat.

I don't know why in- ended up being more common than en- in French, despite not following the normal laws of sound change. It may be due to the influence of Latin spelling. French has a lot of learned words that do not show all of the usual sound changes from Latin. This is particularly common for adjectives; for example, the corresponding adjective to the noun école "school" is scolaire. (A somewhat comparable phenomenon in English is "collateral adjectives" such as cow and bovine.) And it seems to me that in both English and French, negative prefixes such as "in-" and "un-" are most commonly used on adjectives.

If French ended up with more words borrowed from Latin with in- than words inherited from Latin with en-, that might have been a reason why speakers gradually regularized the words starting with en- to make them have the more common, synonymous prefix in-.

Examples of negative en- in English: enemy, enmity, entire

I found only one example in Modern English besides enemy and enmity: entire, which comes from Latin integrum (meaning "whole," compositionally from "untouched"). I learned of this example from W. H. H. Kelke's "An Epitome of English Grammar For the Use of Students, Adapted to the London Matriculation Course and Similar Examinations."

Kelke also mentions enfecte, used by Chaucer as a spelling of "infect." The normal verb infect seems to come from the Latin verb inficio "to dye, stain, poison" which has the prepositional prefix rather than the negative prefix. However, there apparently was a Latin adjective infectus which Wiktionary defines as "not done, unfinished; impossible" and which has the negative prefix. If Chaucer's "enfecte" is in fact an example of the negative prefix "en-," as Kelke says, I guess it must descend from this Latin word.

Examples of negative en- in French and Anglo-French

On the French side, one more word with en- from Latin negative in- is enfant, which compositionally comes from "not speaking." In Modern English, this word has become infant, but according to the Oxford English Dictionary spellings like enfaunt, enfant used to be used. The Modern French word, which retains the spelling with en-, has been borrowed into English more recently in phrases like enfant terrible.

In addition, Skeat lists some Anglo-French forms with negative en-: enferme "infirm" and enfermité "infirmity." However, the equivalent words in modern French are spelled with in-: infirme and infirmité.


As explained in the extract from Etymonline, in is the original prefix, which became en in French. English finally adopted "in" for words of Latin origin and the more common un for Anglo-Saxons ones. The prefix en- still survives with other connotations:


  • a prefix occurring originally in loanwords from French and productive in English on this model, forming verbs with the general sense “to cause (a person or thing) to be in” the place, condition, or state named by the stem; more specifically, “to confine in or place on” ( enshrine; enthrone; entomb); “to cause to be in” ( enslave; entrust; enrich; encourage; endear); “to restrict” in the manner named by the stem, typically with the additional sense “on all sides, completely” ( enwind; encircle; enclose; entwine). This prefix is also attached to verbs in order to make them transitive, or to give them a transitive marker if they are already transitive ( enkindle; enliven; enshield; enface).


  • from in- "not" (see in- (1)) + amicus "friend" related to amare

  • The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.

The prefix in- is actually less common than un- but still used:


  • The most prolific of English prefixes, freely and widely used in Old English, where it forms more than 1,000 compounds. It underwent a mass extinction in early Middle English, but emerged with renewed vigor 16c. to form compounds with native and imported words. It disputes with Latin-derived cognate in- (1) the right to form the negation of certain words (indigestable/undigestable, etc.), and though both might be deployed in cooperation to indicate shades of meaning (unfamous/infamous), typically they are not.
  • 1
    I think you have confused in- (1) with in- (2). The first is a negative, the second is related to the preposition "in".
    – fdb
    Commented Feb 1, 2016 at 10:29
  • @fdb where do I mention 'in' as a preposition in my answer?
    – user66974
    Commented Feb 1, 2016 at 10:40
  • 1
    You don't, but you should have. "Entrust" etc. is from in- (2). "Enemy" is from in- (1).
    – fdb
    Commented Feb 1, 2016 at 10:43
  • @fdb - I mention that part just to show the the profit is still actually used with a different connotation.
    – user66974
    Commented Feb 1, 2016 at 10:47

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