1640s, from flit (n.) + -y (2). Related: Flittiness.
Entries linking to flitty
flit v.
c. 1200, flitten, flytten, flutten "convey, move (a thing) from one place to another, take, carry away," also intransitive, "go away, move, migrate," from Old Norse flytja "to remove, bring," from Proto-Germanic *flutjan- "to float," from extended form of PIE root *pleu- "to flow." Intransitive sense "move lightly and swiftly" is from early 15c.; from c. 1500 as "remove from one habitation to another" (originally Northern English and Scottish)
Theire desire ... is to goe to theire newe masters eyther on a Tewsday, or on a Thursday; for ... they say Munday flitte, Neaver sitte. [Henry Best, farming & account book, 1641]
Related: Flitted; flitting. As a noun, "a flitting, a removal," from 1835.
-y 2
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.