Definition of pain noun from the Oxford Advanced Learner's Dictionary

pain

noun

peɪn

peɪn

see also pains

1 [uncountable, countable] the feelings that you have in your body when you have been hurt or when you are ill/sicka cry of painShe was clearly in a lot of pain.He felt a sharp pain in his knee.patients suffering from acute back painstomach/chest painsYou get more aches and pains as you get older.The booklet contains information on pain relief during labour.This cream should help to relieve the pain. see also growing pains

2 [uncountable, countable] mental or emotional sufferingthe pain of separationI never meant to cause her pain.the pleasures and pains of growing olda life full of pain and suffering3 [countable] (informal) a person or thing that is very annoyingShe can be a real pain when she's in a bad mood.It's a pain having to go all that way for just one meeting.

Idioms

no pain, no gain

(saying) used to say that you need to suffer if you want to achieve something

on/under pain of something

(formal) with the threat of having something done to you as a punishment if you do not obeyThey were required to cut pollution levels, on pain of a £10 000 fine if they disobeyed.

a pain in the neck

(British English also a pain in the arse/backside) (North American English also a pain in the ass/butt) (informal) a person or thing that is very annoying