Green’s Dictionary of Slang

1. to hit, to beat up.

1959

W. Hall Long and the Short and the Tall Act II: Let’s see you slot him, Jock! Drop him one on!

2. (Aus. Und.) to lock into a cell.

1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Slot. [...] also be used as a verb, as in ‘to slot someone’ is to put them in a cell.
2001		(con. 1945–6) P. Doyle Devil’s Jump (2008) 26: If I ever see you again, I’ll slot you.

3. to obtain.

1999

J. Ridley Everybody Smokes in Hell 12: Paris knew the feeling, the need to slot himself some good karma.

4. to kill; thus slotting n.

2000		J.J. Connolly Layer Cake 197: If these two operators were gonna top me, I’d be deceased, despatched, taken out, slotted, gonski.
2003		Herald (Glasgow) 7 Apr. 🌐 In a frequently brutal world, no-one ever mentions the word ‘Kill’. The vogue term for termination by gunfire, bayonet or grenade is ‘slotting’.
2011		J.J. Connolly Viva La Madness 239: They let him uses the slotting crews if things go bandaloo.

5. to hand over.

2013

K. Sampson Killing Pool 18: If you’re extra vigilant you’ll see the sidekick slot Alfie his envelope.