Why  —adv. 1 for what reason or purpose (why did you do it?; i do not know why you came). 2 (prec. By reason etc.) For which (the reasons why i did it). —int. Expressing: 1 surprised discovery or recognition (why, it's you!). 2 impatience (why, of course i do!). 3 reflection (why, yes, i think so). 4 objection (why, what is wrong with it?).  whys and wherefores reasons; explanation. [old english: related to *what]