Someone who can't help smoking lots of weed (or taking other recreational drugs for that matter), even when the situation isn't ideal.
"Will bruv, bill up. I want to get lean as a bean. "
"Ali. We're on the way to the police station cos you've just been mugged. I don't think bunning a zoot is wise, you god damn buzzcat. Afterwards perhaps."
A Buzzcat is someone who interferes where they shouldn't, like putting their nose in where it is not wanted. It can also be used for someone who turns up at an event with being invited.
I went to Dave's party last night and that Buzzcat Fred turned up again. What a chief