Green’s Dictionary of Slang

bold adj.

1. (US teen) unpleasant, unfair.

[US]Detroit Free Press (MI) 6 July 17/1: bold (The teacher was bold) — unfair, not nice.
[UK]P. Baker Fabulosa 289/2: bold [...] 2. unpleasant.

2. (Polari) flamboyantly homosexual.

[UK]P. Baker Fabulosa 289/2: bold 1. audaciously gay.