defying expression or description
e.g. indefinable yearnings
e.g. indescribable beauty
e.g. ineffable ecstasy
e.g. inexpressible anguish
e.g. unspeakable happiness
e.g. unutterable contempt
e.g. a thing of untellable splendor
Synonym: indefinable indescribable ineffable unspeakable untellable