adjectiveWord forms: worse or worst1. not good; of poor quality; inadequate; inferior
 bad workmanship
 bad soil
 bad light for reading
  2. (often foll by at) lacking skill or talent; incompetent
 a bad painter
 bad at sports
 3. (often foll by for) harmful
 bad air
 smoking is bad for you
 4. immoral; evil
 a bad life
 5. naughty; mischievous; disobedient
 a bad child
 6. rotten; decayed; spoiled
 a bad egg
  7. severe; intense
 a bad headache
 8. incorrect; wrong; faulty
 bad pronunciation
 9. ill or in pain (esp in the phrase feel bad)
 10. regretful, sorry, or upset (esp in the phrase feel bad about)
 11. unfavourable; distressing
 bad news
 a bad business
 12. offensive; unpleasant; disagreeable
 bad language
 bad temper
  13. not valid or sound; void
 a bad cheque
 14. not recoverable
 a bad debt
 15. Word forms: badder or baddest slang good; excellent
 16.  go bad
17.  go from bad to worse
18.  in a bad way
19.  in someone's bad books
20.  make the best of a bad job 
21.  not bad
22.  not half bad
23.  too bad
 noun24. unfortunate or unpleasant events collectively (often in the phrase take the bad with the good)
 25. an immoral or degenerate state (often in the phrase go to the bad)
 26. the debit side of an account
 £200 to the bad
 27.  my bad
 adverb28.  not standard badly
 to want something bad
   Word origin
C13: probably from 
bæd-, as the first element of Old English 
bǣddel hermaphrodite