wig (n.) Look up wig at Dictionary.com
1670s, shortened form of periwig. Meaning "person who wears a wig (professionally)" is from 1828.
wig (v.) Look up wig at Dictionary.com
1826, "supply with a wig," from wig (n.). The meaning "to behave hysterically" (usually with out) is attested from 1955, perhaps from notion in flip one's wig. Compare dash my wig!, a former mild imprecation (1797), also wigs on the green (1856), Irish colloquial for "a fight or rumble" (because wigs are likely to get detached from owners in such an event). The verb also had a colloquial sense of "scold severely," attested by 1829, perhaps related to these. Related: Wigged; wigging.