Why

Adverb For which; on account of which; -- used relatively, The reason or cause for which; that on account of which; on what account; ; -- used as a compound relative, For what cause, reason, or purpose, noun_ The cause or intention underlying a given action or situation, A difficult problem or question, A dialectal form of quey, conjunction_ The reason that, The reason, cause, or purpose for which, Usage Problem On account of which; for which, interjection_ Used to express mild surprise, indignation, or impatience, Exclamation of mild surprise