The Word is:”bad”
“a bad diet”
synonyms: substandard, poor, inferior, second-rate, second-class, unsatisfactory, inadequate, unacceptable, not up to scratch, not up to par, deficient, imperfect, defective, faulty, shoddy, amateurish, careless, negligent; More
2.not such as to be hoped for or desired; unpleasant or unwelcome.
synonyms: unpleasant, disagreeable, unwelcome, unfortunate, unfavourable, unlucky, adverse, nasty; More
NORTH AMERICAN informal
“he beat her up real bad”
Source credit: Google