failing to reach an acceptable standard; poor or inadequate
unfavourable
no longer acceptable or usable, because of decay or disrepair
morally objectionable
mischievous or disobedient
(often + at) unskilful or incompetent
disagreeable or unpleasant
bad news
(+ for) injurious or harmful
worse than usual; severe
a bad cold
incorrect or faulty
bad grammar
suffering pain or distress; unwell
am feeling worse
unhealthy or diseased
bad teeth
(often + about) regretful or remorseful
felt bad about refusing
invalid or worthless
a bad cheque
said of a debt: not collectible; not going to be paid
(badder, baddest) chiefly NAmer, informal excellent or admirable
with dishonest intentions
in an unfortunate or undesirable state, e.g. ill, in difficulty, etc
informal quite good
informal regrettable; unfortunate
informal said dismissively or philosophically, unfortunate but unable to be changed and therefore to be accepted