bad boy noun (chiefly US inf)

Any impressive thing

bad debt noun

A debt that cannot be recovered and is therefore written off as a loss

bad hair day noun (informal)

A day that starts badly (characterized by difficulty with one's hair) and gets worse, a day one would rather not have to face

badˈlands plural noun

1. Greatly eroded wasteland in South Dakota
2. Any similar eroded region

bad language noun

Swearing

badly off adjective

Poorly provided esp with money

badˈman noun (chiefly US)

An outlaw

badˈmouth transitive verb (informal)

To criticize, malign

bad news plural noun

1. Any unwelcome, upsetting or irritating event, or a report of such
2. Someone or something troublesome, irritating, etc (slang)

bad shot noun

A wrong guess

bad-temˈpered adjective

Easily annoyed, sulky

bad trip noun (informal)

An episode of terrifying hallucinations and physical discomfort resulting from taking a drug, esp LSD

bad'ware noun same as malware

big bad see under big¹

feel bad about (informal)

To be sorry about, regret

from bad to worse

Into an even worse situation

go bad

To decay, become mouldy or putrid

go to the bad

To go to moral ruin

in a bad way (informal)

1. Ill
2. In trouble

in someone's bad books

Unpopular with someone

make the best of a bad job (informal)

To do the best one can in unfavourable circumstances

my bad (US sl)

A phrase used to acknowledge that one has made a mistake

not bad

Fairly good

not half bad (informal)

Pretty good, excellent

take the bad with the good

To accept unpleasant things along with pleasant ones

too bad (informal)

1. What a pity!
2. Regrettable, a shame

to the bad

In deficit

with a bad grace

Ungraciously