Has there ever been an antonym for "benefit" that includes the latin affix "neg-"?

Question

I understand bene to roughly mean well, good, or rightly so from Latin, while neg- coming from Latin negare to roughly mean deny, negate, or against.

The words benefit, beneficial, and benefactor all represent a person or characteristic that yields a positive result or influence. Do any of these words have an antonym that includes the neg- affix? Are there any positive bene-based words that have a neg-based word as its antonym?

Mono- and poly- seem to be frequently paired in an antonymic relationship — does this occur with bene- and neg-?

*Background: I started titling a pro and con list with benefit, and found myself searching for negefit.

Answer 1

No, bene- and neg- are not used to form antonyms in either English or Latin. Their root meanings of "good" and "deny" are roughly opposed, but not antonyms in English either.

As others have mentioned, mal-, meaning "bad" is the typical antonym to bene-, as in benediction/malediction (literally "good speech", "bad speech").

Posi- may seem like it should oppose negi- because of the positive/negative pairing, but it actually comes from a root word meaning "put" or "place." Affirm- is probably a better opposite to neg- as in affirmative/negative and affirmation/negation.

Answer 2

The Oxford Dictionaries online finds

malefit A misfortune, a disadvantage.

from their British & World English Dictionary, supposedly from the 18th century. No provenance or examples.

The printed OED doesn't record this word, but does have malefice meaning either sorcery (first attribution to Chaucer in 1324) marked as archaic or an evil deed or mischief (first attribution to Spenser's poem "Mother Hubberd's Tale" in 1591) marked as obsolete or archaic:

He crammed them with crumbs of Benefices, And did fill their mouths with meeds of malefices

(There's also an obsolete astrological use meaning the obvious thing.)

The OED finds both benefit and benefice from the 1300s. The former prospered into five major senses (including such as the kind of benefit that's a charity event); the latter fell into obsolescence, taking its antonym with it, perhaps because of its special meaning associated with sorcery. Note that malefit would seem to have arrived long after benefit.

Answer 3

Perhaps you were thinking of nugatory? The Oxford Dictionaries online gives

nugatory of no value or importance

Answer 4

See https://www.powerthesaurus.org/benefit+negative/antonyms
and https://www.powerthesaurus.org/beneficial+negative/antonyms

“Negative” is more often than not accepted as an antonym to the noun “benefit” and the adjective “beneficial” — so it would be appropriate to contrast “One benefit of this procedure” with “One negative of this procedure”; though a phrase like “negative effect” or “negative impact” would be better.