Inexpressible
Part of speech: adjective
Definition: Unable to be expressed.
Example sentence: There, in the chords and melodies, is everything I want to say. The words just jolly it along. It's always been my way of expressing what, for me, is inexpressible by any other means.
Indescribable
Part of speech: adjective
Definition: Impossible, or very difficult to describe.Exceeding all description.
Example sentence: I could never ever say enough about Matt Amato. He has an indescribable presence; this warm, loving, serene calm with intense interest and excitement bubbling beneath his exterior.