1. verb, slang To throw, chuck, or hurl something. Primarily heard in Australia. The teacher piffed her coffee mug into the wall in anger. The child started piffing his toys around the room during his tantrum.
2. adjective, slang Very sexually attractive; fit. Primarily heard in UK. There's a couple piff girls in my class, but they're all a bit posh and stuck up. Yeah, she's looking well piff these days!
3. adjective, slang Very good; excellent. Primarily heard in UK. I'm telling you, that film is piff! The burger was piff, and pretty cheap, too!
slang Drunk. I was pretty piffed by the time we left the bar. He just spends every evening getting piffed with his friends.