1. slang A positive occurrence, typically beyond one's hopes or expectations; a bonus. I've had the time of my life working on this project. If I make money from it, then that's just gravy.
2. slang Easily obtained profit or money. A: "I can't believe we made so much money from that simple project." B: "I know, it's all gravy."
3. slang Great or excellent. Try not to get so stressed out, man—everything's gravy.
See Good gravy!