the habit of biting one's fingernails.

(idiomatic, vulgar) Life can be tough, unpleasant, unrewarding.

(slang, idiomatic) To not do something out of fear; chicken out. / (slang, idiomatic) To back out of an agreement for any reason. / (slang) To complain; to yell at.

Alternative form of bittercress

(pharmacology) Used to form generic names of barbiturate drugs.

past participle of bite the bullet

Alternative form of Mishmi bitter

(archaic) The bitter tonic root of a Chinese species of goldthread.

(intransitive) To retaliate. / (transitive) To repress (an emotion).

(informal) wretched or sordid; mean