1. Referred to someone who is in the state of being very strongly envious of someone else's advantages or belongings.
2. Can also be used as a nickname, defined as the above.
Person A: "Gosh, I hate her. She's so talented and she's really pretty and her boyfriend is just amazing..."
Person B: "Ooh, do I hear someone coveting?"
Person A: "Psh, I'm not jealous. Just saying..."
Person B: "Oh, you're such a jealous mealous, don't deny it."
Person 1: "This car sucks... I wish I had one of those nice, shiny sports cars like that one guy has..."
Person 2: "Whatever, Mr. Jealous Mealous..."
Person 1: My life sucks. It's not worth living anymore. So I tried to hang myself three times last night, but the first time I fell out of the noose, the second time I was thirsty, and the third time my mom walked in and put me in my straight jacket.
Person 2: Wow. That's some epic mortality fail.