Green’s Dictionary of Slang

screwy adj.

1. [mid-19C] drunk [screwed adj. (1)].

2. [mid–late 19C] mean.

3. [late 19C] worn out [screwed adj. (3)].

4. (orig. US) in senses derived from a screw loose under screw n.1

(a) [late 19C+] foolish, stupid, insane.

(b) [1920s+] odd, strange.

(c) [1930s] (US) suspicious, alarmed.

(d) [1930s+] illegal; counterfeit.

(e) [1930s] (US) sexually obsessed.

5. [1940s+] weak, malfunctioning, broken.