the GNU version of the Collaborative International Dictionary of English
adj. Not capable of expression or utterance in language; ineffable; unspeakable; indescribable; unutterable.
The Century Dictionary and Cyclopedia
Not expressible; incapable of being expressed; that cannot be uttered or represented in words; unspeakable; unutterable: as, inexpressible grief or joy.
Synonyms Unspeakable, indescribable, ineffable.
Trousers; “unmentionables.”
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. defying expression
Word Usage
"After silence, that which comes nearest to expressing the inexpressible is music"