Green’s Dictionary of Slang

substandard, second-rate.

2001		N. Macdonald Graffiti Subculture xi: Dry, lame, wak: Something which is bad or of substandard quality.
2017		theculturetrip.com ‘Guide to London Slang 10 Jan. 🌐 Dry– dull, boring, unfunny like a bad joke your dad or boss might tell.