Green’s Dictionary of Slang

1. to beat, to strike, to thrash.

1808		in Jamieson Etym. Dict. Scot. Lang.
1989		J. Morton Lowspeak 91: Lamp – 2. to hit in the face.
2001		N. Griffiths Sheepshagger 240: Fuckin lucky there Llýr, I was just about to fuckin lamp yew one I was.
2004		C. Brookmyre Be My Enemy 166: Energetically lamping Rory with a ‘Shut Up You Smug Tory Twat’ baseball bat.
2012		(con. 1980s) I. Welsh Skagboys 269: One ay these days the big felly’s gaunny turn roond n lamp that stroppy wee fucker.
2012		C. Black ‘Topless Vampire Bitches’ in C. Rhatigan and N. Bird (eds) Pulp Ink 2 [ebook] I swear if he changes his mind one more time I’m goonna fuckin’ lamp him!
2020		A. Parks Bobby March Will Live Forever 166: ‘[T]he mood I’m in I’ll lamp the bastard’.
2022		Twitter 19 Oct. 🌐 Any chance someone does the decent thing and lamps [Jacob Rees-]Mogg?

2. (W.I.) to trick, to deceive.

1960

cited in Cassidy & LePage Dict. Jam. Eng. (1980).