- contraction of why is: Why's dinner so late?
- for what? for what reason, cause, or purpose?: Why did you behave so badly?
- for what cause or reason: I don't know why he is leaving.
- for which; on account of which (usually after reason to introduce a relative clause): the reason why he refused to go.
- the reason for which: That is why he returned.
- a question concerning the cause or reason for which something is done, achieved, etc.: a child's unending hows and whys.
- the cause or reason: the whys and wherefores of a troublesome situation.
- (used as an expression of surprise, hesitation, etc., or sometimes a mere expletive): Why, it's all gone!
Origin of why
- for what reason, purpose, or cause?why are you here?
- (used in indirect questions)tell me why you're here
- for or because of whichthere is no reason why he shouldn't come
- (usually plural) the reason, purpose, or cause of something (esp in the phrase the whys and wherefores)
- an introductory expression of surprise, disagreement, indignation, etcwhy, don't be silly!
Word Origin and History for why's
Old English hwi, instrumental case (showing for what purpose or by what means) of hwæt (see what), from Proto-Germanic *khwi (cf. Old Saxon hwi, Old Norse hvi), from PIE *qwei, locative of *qwo- "who" (cf. Greek pei "where"). As an interjection of surprise or to call attention to a statement, recorded from 1510s.