A left-handed compliment is a criticism couched as a compliment, a compliment with two meanings, one of which is unflattering to the receiver. It is also known as a backhanded compliment.
- You are very competent for someone so inexperienced.
- That dress is really sharp. It really makes you look so slim!
- You have such nice handwriting for a left-hander
- Your son is more handsome than I would have expected
If you come across any more good examples, please post them as comments below.