A compliment, but instead of being complimenting, it's more of a smack in the face.
"You looked really skinny today... What happend? BAM!"
"Damn, I used another Clompliment didn't I?"
When you're trying to give someone a compliment, and then realise it was more of an insult. Generally followed by backtracking and apologies.
"That skirt is great at hiding your fat thights!"
"Oh my gosh I'm so sorry - that was a bit of a clompliment"