Green’s Dictionary of Slang

guy n.2

1. [late 19C+] (US) a man or boy; thus main guy under main adj.

2. [1910s+] a general term of address, repopularized in 1970s+ among young UK blacks, and now in general teen use.

3. [late 19C+] (US) a woman.

4. [1960s] a boyfriend, a lover.

5. [1970s+] a person, irrespective of gender.

6. [1980s+] (US campus) in ironic reversal, an incompetent, an inadequate.

7. [1980s+] (US) an object, a thing.