bad adj.
1 not good; serious
VERBS be, look, sound | become, get The weather got very bad later in the day.
ADV. extremely, really, very | enough Things are bad enough without our own guns shelling us. | fairly, pretty, quite, rather John's in a pretty bad mood this morning.
PREP. at He's really bad at maths. | for Smoking is very bad for you.
2 not safe to eat
VERBS be, look, smell, taste The sausages tasted bad. | go, turn This meat has gone bad.
3 guilty/sorry
VERBS feel
ADV. really, very | enough I feel bad enough without you constantly telling me how it was all my fault! | fairly, pretty, quite, rather
PREP. about She felt pretty bad about leaving him.
You can also check other dicts: bad (English, 中文解释 ), wordnet sense, Collins Definition