"Caractérisé" is used to describe a type of behaviour which has become systematic, characteristic, part of a person's normal way of behaving. It can de used to define particular behaviour in particular specified circumstances.

With respect to previous suggestions, that is a little different from 'utmost' or 'blatant'. The meaning of "caractérisé" suggests that a type of behaviour is repeated, characteristic, common... not quite the same thing.

I would probably turn the sentence around to read a little more naturally to convey the meaning that the person has systematically or consistently acted in bad faith.

Check a good standard dictionary for meaning.