Gank

To GANK someone is to steal their possessions in part or in full, often synonymous with drugs in social situations, the reference is "I've been ganked", which means you have been ripped off by either your drug dealer or someone close to you. Drug Dealers also get GANKED by people on a regular basis, because they know that most GANKS are never reported to the Police, and are therefore worth the risk.

If you GANK your mate, you typically have stolen some or all of their drugs.
"Hey shall we smoke some gear"
"Yeah we could have yesterday but Craig and his mate came over and I got GANKED".

Mum: Are you going to the concert tonight? Watch out where you smoke or snort your shit, or u might get GANKED