in bad form
Violating social custom or accepted behavior.
When Bob went to the opera in blue jeans and without a tie, his father-in-law told him that it was in bad form.
in bad
Out of favor; unpopular; in difficulty; in trouble. Usually used with with.
No, I can't go swimming today. Father told me to stay home, and I don't want to get in bad.
Mary is in bad with the teacher for cheating on the test.
The boy is in bad with the police for breaking windows.