Green’s Dictionary of Slang

1. (US drugs) exhibiting the signs of addiction to crack cocaine.

2001

J. Stahl Plainclothes Naked (2002) 145: The tweaky guy came back on, panting and talking fast.

2. nerve-racking, suspenseful.

2007

J. Stahl ‘Pure’ in Love Without 170: The tweakiest time of all was right now.