Green’s Dictionary of Slang

sick adj.1

1. [mid-19C] (US Und.) imprisoned.

2. [mid-19C; 1980s+] (US campus) a general pej., of poor quality, unfashionable, unappealing, stupid, weak, bizarre.

3. [mid-19C+] annoyed, worried, disgusted, often with undertones of jealousy.

4. [1950s+] (US) mentally disturbed, psychopathic, esp. in a sadistic way.

5. [1950s+] (orig. US) morbid, depraved, e.g. a sick sense of humour.

6. [1980s+] excellent, first-rate [on the bad = good model].

In compounds

sick-ass (adj.)

see separate entry.

In phrases

knock someone sick (v.) (also sick someone)

[late 19C-1920s] to amaze, to astonish; to disorientate, stun.

sick and wrong (adj.)

[1980s+] (US campus) a general pej., absolutely impossible, unthinkable, totally disgusting; also used ironically.

sick as… (adj.)

see separate entry.

sick in fourteen languages (adj.)

[late 19C] (US) very sick.