(informal) To deliberately treat someone in an unfair or harmful manner.

plural of dirty old man

A form of mountainboard.

plural of dirtboard

(slang) Foul play, misconduct, underhandedness.

Resistant to dirt.

plural of dirtball

(slang, derogatory) A dirty or sleazy person.

Moderately dirty; somewhat dirty.

(idiomatic) One or more unpleasant tasks, assignments, or employment duties, especially those of a disreputable or illicit nature.