whisper (v.) Look up whisper at Dictionary.com
Old English hwisprian "speak very softly, murmur" (only in a Northumbrian gloss for Latin murmurare), from Proto-Germanic *hwis- (cognates: Middle Dutch wispelen, Old High German hwispalon, German wispeln, wispern, Old Norse hviskra "to whisper"), from PIE *kwei- "to hiss, whistle," imitative. Transitive sense is from 1560s. Related: Whispered; whispering. An alternative verb, now obsolete, was whister (late 14c., from Old English hwæstrian), and Middle English had whistringe grucchere "a slanderer."
whisper (n.) Look up whisper at Dictionary.com
1590s, from whisper (v.).