(Britain, informal) An ordinary member of the public who intervenes, often at personal risk, to stop a troublemaker, hooligan or ne'er-do-well in the act of committing a crime.

simple past tense of could do with / simple past tense of can do with

(idiomatic) To be destined for someone.

To reflect on and reframe an event; to reconsider.

(idiomatic) To be experienced in worldly matters; to be seasoned, not naive.

(idiomatic) To punish or subdue someone.

To speak to someone in private.

Used other than figuratively or idiomatically: see let, have, it. / (idiomatic) To attack someone with great force. / (idiomatic) To verbally assail someone.

(US, chiefly in the negative) To have a personal stake in the issue.

(idiomatic) To understand a person's character, capabilities, or situation. / Used other than figuratively or idiomatically: see have, someone's, number.