guac

Something that is over the top, excessive, dramatic, ridiculous, or unnecessary; extra

When you ask for guac(amole) on your burrito at Chipotle, the server always says "Guac is extra, is that okay?" Thus, when someone is being extra, they are being guac.

Jake: "Did you see Katie's outfit today? She's wearing 3 necklaces and 8 inch heels. She is so guac!"