Green’s Dictionary of Slang

freaky adj.1

[freak n.1 (2) + sfx -y]

1. [late 19C+] odd, bizarre, unnerving.

2. [1960s+] (drugs) hallucinogenic, psychedelic.

3. [1970s] (drugs) strong, powerful.

4. [1980s] nervous.

In compounds

freaky-deaky (adj.)

[1980s+] (US) weird, bizarre.

freaky deal (v.)

[2000s] (US) to cheat, to deceive.

freaky-freak (n.) [freak n.1 (2)]

[1990s+] an eccentric; also used as a term of affection.

freaky-straight (n.) [straight n.2 (1)]

[1960s] a person who either looks ordinary but behaves unusually, or one who looks unusual but behaves normally.