1 cause/motive/justification; explanation of sth
ADJ. cogent, good, sound, strong | compelling, convincing | plausible | adequate, sufficient | bona fide, legitimate, valid | wrong He married her for all the wrong reasons. | opposite Tom's problem was that he lacked confidence; Ed failed for precisely the opposite reason. | important | special | chief, main, major, primary, principal | only, simple, sole The only reason I didn't become a professional golfer was because of my family commitments. I was never good at playing the trumpet for the simple reason that I never practised. | real, underlying She did not tell him the real reason for her change of heart. The underlying reasons for these differences will be explored in depth in the next chapter. | very There is an assumption that a state will protect its citizens. That is the very reason for the existence of states. | apparent, particular He was attacked for no apparent reason. | no earthly, (no) possible Surely there is no earthly reason why you wouldn't want to come with us? | clear, obvious The reasons for her decision soon became clear. | unclear | logical | understandable | justifiable | inexplicable, unexplained, unknown For some unexplained reason the pilot jettisoned all his fuel shortly after take-off. | unspecified | unconnected dismissal for reasons unconnected with redundancy | personal | sentimental | selfish | professional | commercial, economic, financial, legal, political, social, technical | practical, pragmatic | security | health | humanitarian
VERB + REASON be aware of, see We see no reason why this band shouldn't be a huge success. | have I don't know why he did that, but I'm sure he had his reasons. I have no reason to believe that she was lying to me. | cite, give (sb/sth), set out, state Give me one good reason why I should help you. In the letter she carefully set out her reasons for leaving. | cite sth as, give sth as | suggest | explain | understand | uncover
PREP. by ~ of (formal) persons in need of care by reason of (= because of) old age | for a/the ~ procedures carried out for reasons of national security | for ~ of (formal) For reasons of security, you are requested to keep your luggage with you at all times. | with/without ~ They complained about the food, and with good reason (= rightly). | ~ against There are obvious reasons against such a move. | ~ behind We are trying to uncover the reasons behind her decision. | ~ for They didn't give any reason for the delay.
PHRASES all the more reason If he's unwell, that's all the more reason to go and see him. | all sorts of reasons People buy things for all sorts of reasons. | any/every/little/no/one/some reason I know you're angry with me, and you have every reason (= very good reasons) to be. | for reasons best known to yourself For reasons best known to herself she has turned down the offer. | for whatever reason people who, for whatever reason, are unable to support themselves | a number/variety of reasons, rhyme or reason There's no rhyme or reason (= logic) to the new opening hours.
2 power to think logically; what is possible/right
VERB + REASON lose He seems to have lost all sense and reason. | be open to, listen to, see I tried to persuade her, but she just wouldn't listen to reason.
PREP. beyond ~ He was beyond all reason. | within ~ I'll lend you the money you need?within reason, of course!
PHRASES an appeal to reason The residents hope that an appeal to reason (= asking the rioters to be reasonable) will end the rioting. | it stands to reason It stands to reason (= it is logical) that she wouldn't want them to find out about her personal problems. | the voice of reason She was always the voice of reason, persuading him not to buy things they couldn't afford.