Colloquial: a schemer or intriguer; one entangled in and fond of dubious affairs and manoeuvres.
Colloquial: a whirl/round; slang for a confusing affair, a love-affair, or dizziness ('chakkar chal raha hai').
Colloquial: slick and cunning, an operator who works every angle; also means 'switched on' or 'in operation'.