Definition:
1. Absolutely fabulous, smashing, wonderful, much appreciated.
2. Outrageous, stupid, maddening, mean, etc.
Used by UK speakers where Americans might say "totally awesome" or "way to go".
Usage:
That chocolate cake you made for my birthday was brilliant.
It's great the way you claimed all the responsibility for the report I worked on with you--that's just brilliant, isn't it?
