indescribable vs untellable

indescribable and untellable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
indescribable	No	Yes	No	No
untellable	No	Yes	No	No

As adjectives, indescribable and untellable are synonyms defined as:

Other synonyms of indescribable include indefinable, ineffable, unspeakable, unutterable.

indescribable (adjective)	untellable (adjective)
defying expression or description	defying expression or description