"slender," 1560s, from twig + -y (2). The famous 1960s English model was born Lesley Hornby (1949). The older adjectival form was twiggen "made of twigs" (1540s).
Entries linking to twiggy
twig n.
Old English twig "twig, branch, shoot, small tree," from Proto-Germanic *twigga "a fork" (source also of Middle Dutch twijch, Dutch twijg, Old High German zwig, German Zweig "branch, twig"), from PIE *dwi-ko-, from root *dwo- "two." Compare Old English twisel "fork, point of division."
-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.