1 general:: Phrase(s): hats off to someone or something Fig. let us salute or honor someone or something. • Hat’s off to Perry for planning the dinner and finding such a good band.
McGrawhill's American Idioms And Phrasal Verbs
2 general:: Congratulations to, as in Hats off to Claire! She's set a new record for the mile. This expression alludes to taking off one's hat as a sign of respect. [Mid-1800s]
American Heritage Idioms