"Hats off to" is an idiom that acknowledges appreciation, admiration or respect for someone or something. However, there are certain antonyms or opposite phrases that express disapproval, contempt, or criticism instead. Examples of these opposites are "thumbs down to," "disregard for," "criticize greatly" and "look down on." Instead of hats off to a person, one can say "thumbs down to" or "look down on" to convey disapproval or criticism. In summary, antonyms for "hats off to" are phrases that demonstrate the opposite sentiment, and express criticism or disapproval rather than admiration or approval.