Word Origin & History
O.E. hwistlian, from P.Gmc. *khwis-, of imitative origin. Used also in M.E. of the hissing of serpents. The noun meaning "tubular musical instrument" is from O.E. hwistle. To wet one's whistle "take a drink" (late 14c.) originally may have referred to pipes, or be an allusion to the throat as a sort
of pipe. To whistle for (with small prospect of getting) is probably from nautical whistling for a wind. Figurative use of whistle-blower first attested 1970. To whistle "Dixie" is from 1940. Phrase clean as a whistle is recorded from 1878; railroad whistle stop (at which trains stop only if the engineer hears a signal from the station) is recorded from 1934.