Pain  —n. 1 any unpleasant bodily sensation produced by illness, accident, etc. 2 mental suffering. 3 (also pain in the neck or arse) colloq. Troublesome person or thing; nuisance. —v. 1 cause pain to. 2 (as pained adj.) Expressing pain (pained expression).  be at (or take) pains take great care. In pain suffering pain.