Merriam-Webster Collegiate Dictionary - whatever

 I. pronoun  Date: 14th century  1.  a. anything or everything that take ~ you want  b. no matter what ~ he says, they won't believe him  c. whatnot enjoys skiing, hiking, or ~  2. what 1a(1) — used to express astonishment or perplexity ~ do you mean by that  II. adjective  Date: 14th century  1.  a. any…that ; all…that buy peace…on ~ terms could be obtained — C. S. Forester  b. no matter what money, in ~ hands, will confer power — Samuel Johnson  2. of any kind at all — used after the substantive it modifies with any or with an expressed or implied negative in any order ~ — W. G. Moulton no food ~  III. adverb  Date: 1870 in any case ; ~ the case may be — sometimes used interjectionally to suggest the unimportance of an issue or decision between alternatives go see a movie, watch TV,— ~