1) Beyond expression 2) Beyond words 3) Deep 4) Hard to define 5) Impalpable 6) Imperceptible 7) Impossible to put into words 8) Indefinable 9) Indefinite 10) Indescribable euphoria 11) Ineffable 12) Inexpressible 13) Not describable 14) Obscure 15) Overwhelming 16) Too unusual for words 17) Unexpressible 1) Inconceivable 2) Indefinable 3) Ineffable 4) Inexpressible 5) Insubstantial 6) Unexpressible 7) Unspeakable 8) Untellable 
• (a.) Incapable of being described.
In`de·scrib'a·ble adjective Incapable of being described. -- 
indescribable 1. That which cannot be described; that does not admit of exact description; indefinite, vague. 2. That which transcends description; too great, beautiful, etc. to be adequately described.
not describable; too extraordinary for description: a scene of indescribable confusion; indescribable euphoria.