Origin and history of garnishment

late 14c., "to decorate, adorn, beautify," also in Middle English "equip (a place) for defense; arm (oneself) for battle; prepare to defend," from Old French garniss-, present-participle stem of garnir "provide, furnish; fortify, reinforce" (11c.), from Frankish *warnjan, from Proto-Germanic *warnon "be cautious, guard, provide for" (source also of Old High German warnon "to take heed," Old English warnian "to take warning, beware;" see warn), from PIE root *wer- (4) "to cover."

Sense evolution is from "arm oneself" to "fit out" to "embellish," which was the earliest meaning in English. Culinary sense of "to decorate a dish for the table" predominated after c. 1700. Older meaning survives in legal sense of "to warn or serve notice of attachment of funds" (1570s). Related: Garnished; garnishing.

common suffix of Latin origin forming nouns, originally from French and representing Latin -mentum, which was added to verb stems to make nouns indicating the result or product of the action of the verb or the means or instrument of the action. In Vulgar Latin and Old French it came to be used as a formative in nouns of action. French inserts an -e- between the verbal root and the suffix (as in commenc-e-ment from commenc-er; with verbs in ir, -i- is inserted instead (as in sent-i-ment from sentir).

Used with English verb stems from 16c. (for example amazement, betterment, merriment, the last of which also illustrates the habit of turning -y to -i- before this suffix).

The stems to which -ment is normally appended are those of verbs; freaks like oddment & funniment should not be made a precedent of; they are themselves due to misconception of merriment, which is not from the adjective, but from an obsolete verb merry to rejoice. [Fowler]