Green’s Dictionary of Slang

1. (UK black) to hit hard; to fire a weapon.

2004		Urban Dict. 14 Oct. 🌐 To ‘clart’ someone is to smack them one. ‘I oughtta clart you one round your boney head, you naughty!’.
2020		Urban Dict. 23 June 🌐 Clart To hit someone or something with considerable force.
2022		Digga D. ‘G Lock’ 🎵 I cross the Blue bridge, clart off two quick (Bap) / Then park the broomstick [...] (Bap, bap, boom).

2. (UK black) to have sexual intercourse.

2020

Urban Dict. 2 Nov. 🌐 To clart is to take part in sexual intercourse. ‘Yo im not inna the dating ting lets just clart’.