Green’s Dictionary of Slang

crappy adj.

[crap n.1 + sfx -y]

1. [mid-19C+] fouled with excrement.

2. [1920s–30s] (UK, Glasgow) terrified.

3. [1920s+] (also krappy) second-rate.

4. [1950s–60s] in colour, reminiscent of excrement.

5. [1950s+] unpleasant, distasteful.

6. [1960s+] unwell.