1) Beyond description 2) French word used in English 3) Indefinable 4) Indescribable 5) Inexpressible 6) Too sacred to be uttered 7) Unable to sum up in words 8) Unexpressible 9) Unspeakable 10) Untellable 11) Unutterable 1) Indescribable 2) Inexpressible 3) Sacred 4) Tabu 5) Unexpressible 6) Unnameable 7) Unspeakable 8) Untellable 9) Unutterable 
• (a.) Incapable of being expresses in words; unspeakable; unutterable; indescribable; as, the ineffable joys of heaven.
In·ef'fa·ble adjective [ Latin ineffabilis : confer French ineffable . See In- not, and Effable , Fame .] Incapable of being expressed in words; unspeakable; unutterable; indescribable; as, the ineffable joys of heaven. « Contentment with our lot . . ...
to great to be described in words 
[adj] - too sacred to be uttered
ineffable, ineffability 1. Incapable of being expressed in words. 2. Too great, or extreme, to be expressed or described in words.
unnameable adjective too sacred to be uttered; `the ineffable name of the Deity`
incapable of being expressed or described in words; inexpressible: ineffable joy. · not to be spoken because of its sacredness; unutterable: the ineffable name of the deity.
[SAT terms] defying expression or description
defying expression or description defying expression or description