Main Entry: un·speak·able

Pronunciation: \-ˈspē-kə-bəl\

Function: adjective

Date: 14th century

1 a : incapable of being expressed in words : unutterable b : inexpressibly bad : horrendous <unspeakable living conditions> <unspeakable evil>
2 : that may not or cannot be spoken <the bawdy thoughts that come into one's head — the unspeakable words — L. P. Smith> <unspeakable collections of consonants — Rosemary Jellis>

— un·speak·ably \-blē\ adverb