Green’s Dictionary of Slang

inferior, second-rate.

1993		I. Welsh Trainspotting 306: The nondy cunt crashes intae the wall, then staggers backwards.
1994		I. Welsh ‘Sport for All’ in Acid House 152: What a fuckin nondy cunt!
2012		(con. 1980s) I. Welsh Skagboys 479: The nondy fucker tried to brek intae a chemist’s.