Monkey
mid 16th century: of unknown origin, perhaps from Low German.
wiktionary
Uncertain. May be either derived from Middle English monk, or borrowed from Middle Low German Moneke, name of the son of Martin the Ape in Reynard the Fox (which may represent an unattested colloquial *moneke, which in turn is possibly a diminutive from Middle French monne, from Old Spanish mona, shortening of mamona, variant of maimón, from Arabic مَيْمُون (maymūn, “baboon”)). Compare Old French Monequin.
etymonline
monkey (n.)
1520s, also monkie, munkie, munkye, etc., not found in Middle English (where ape was the usual word); of uncertain origin, but likely from an unrecorded Middle Low German *moneke or Middle Dutch *monnekijn, a colloquial word for "monkey," originally a diminutive of some Romanic word, compare French monne (16c.); Middle Italian monnicchio, from Old Italian monna; Spanish mona "ape, monkey." In a 1498 Low German version of the popular medieval beast story Roman de Renart ("Reynard the Fox"), Moneke is the name given to the son of Martin the Ape; transmission of the word to English might have been via itinerant entertainers from the German states.
The Old French form of the name is Monequin (recorded as Monnekin in a 14c. version from Hainault), which could be a diminutive of some personal name, or it could be from the general Romanic word, which may be ultimately from Arabic maimun "monkey," literally "auspicious," a euphemistic usage because the sight of apes was held by the Arabs to be unlucky [Klein]. The word would have been influenced in Italian by folk etymology from monna "woman," a contraction of ma donna "my lady."
In general, any one of the primates except man and lemurs; in more restricted use, "an anthropoid ape or baboon;" but popularly used especially of the long-tailed species often kept as pets. Monkey has been used affectionately or in pretended disapproval of a child since c. 1600. As the name of a type of modern popular dance, it is attested from 1964.
Monkey suit is from 1876 as a type of child's suit; by 1918 as slang for "fancy dress clothes or uniform." To make a monkey of "make a fool of" is attested from 1851. To have a monkey on one's back "be addicted" is 1930s narcotics slang, though the same phrase in the 1860s meant "to be angry." There is a story in the Sinbad cycle about a tormenting ape-like creature that mounts a man's shoulders and won't get off, which may be the root of the term. In 1890s British slang, to have a monkey up the chimney meant "to have a mortgage on one's house." The Japanese three wise monkeys ("see no evil," etc.) are attested in English by 1891.
monkey (v.)
1859, "to mock, mimic" (as a monkey does), from monkey (n.). Meaning "play foolish tricks" is from 1881. To monkey (with) "act in an idle or meddlesome manner" is by 1884. Related: Monkeyed; monkeying.
