Green’s Dictionary of Slang

indecisive, variable, vacillating.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1873		Sl. Dict.
2001		J. Haseley ‘The Hammer’ Week 11 on Who Do I start? 🌐 He’s off and on every week. The lack of consistency is enough for me not to start him.