(chiefly Britain, idiomatic) To remain cheerful; keep smiling.

(idiomatic) To keep quiet; to keep a secret; to not tell.

(intransitive, idiomatic) to maintain a background awareness of something; to remain alert to changes without it occupying one's full attention.

(idiomatic) To maintain one's concentration fixed on one important theme.

(idiomatic) To not commit to a decision, to keep various options available.

To keep one's own business private; to be discreet, careful, or circumspect in what one says concerning one's own thoughts, deeds, or situation.

(idiomatic) To keep a secret; to refrain from speaking indiscreetly or carelessly; broadly, to refrain from speaking altogether.

(idiomatic) To be tough; to have endurance; to have the capacity to absorb stress or damage, but still be able to function.

(idiomatic) To stay out of trouble, especially by avoiding unlawful behavior.

(idiomatic, colloquial) To maintain daily routine and provide the necessities of life in a home or community.