Green’s Dictionary of Slang

radio (rental) adj.

insane, mad.

1973		(con. mid-1960s) J. Patrick Glasgow Gang Observed 120: Ah’m goin’ radio.
1996		A. Close Official and Doubtful 62: The neighbours must’ve thought I was radio rental.
1999		J. Baker Walking With Ghosts (2000) 291: Careful. He’s Radio Rental.
2002		D. Shaw ‘Dead Beard’ at www.asstr.org 🌐 But the problem was that Dionne was very partial to being melvyn bragged by everything in strides, a hobby she didn’t dare indulge in with Lingers around, what with him being totally radio rental and likely to cut her to pieces if she got caught having it away on the side.