1) Somebody who is inept, stupid, or useless (adj.)
2) The greatest band on earth; composed of Maynard James Keenan, Adam Jones, Justin Chancellor, and Danny Carey. They were formed in Los Angeles in 1990.
1. Person One: Some guy put something funny in my drink, and when I woke up this morning, my anus was all bloody and squishy!
Person Two: You sir, are a fucking tool.
2. I'm going to a Tool concert today. Maynard is the awesomeness.