Grandiloquent dictionary. 2006.
siffilate — sif·fi·late … English syllables
siffilate — v.t. whisper … Dictionary of difficult words
siffilate — ˈsifəˌlāt verb ( ed/ ing/ s) Etymology: modification (influenced by sibilate) of French siffler to whistle, from Middle French : whisper … Useful english dictionary