funny adj.

"diversion, amusement, mirthful sport," 1727, earlier "a cheat, trick" (c. 1700), from verb fun (1680s) "to cheat, hoax," which is of uncertain origin, probably a variant of Middle English fonnen "befool" (c. 1400; see fond). Scantly recorded in 18c. and stigmatized by Johnson as "a low cant word." Older senses are preserved in phrase to make fun of (1737) and funny money "counterfeit bills" (1938, though this use of the word may be more for the sake of the rhyme). See also funny. Fun and games "mirthful carryings-on" is from 1906.

adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.