early 15c. (in reference to the penis), from wrinkle (n.) + -y (2). As teen slang noun for "old person," from 1972 ("old" being relative; a British reference from 1982 applies it to people in their 40s).
"fold or crease in the extenal body," late 14c.; in cloth or clothing from early 15c., probably from wrinkle (v.). Meaning "defect, problem" first recorded 1640s; that of "idea, device, notion" (especially a new one) is from 1817.
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).