1
general::
Phrase(s): pay someone a backhanded compliment [and] pay someone a left-handed compliment
Fig. to give someone a false compliment that is really an insult or criticism. • John said that he had never seen me looking better. I think he was paying me a left-handed compliment. • I’d prefer that someone insulted me directly. I hate it when someone pays me a backhanded compliment—unless it’s a joke.
McGrawhill's American Idioms And Phrasal Verbs