Indescribable (6)
I believe the answer is:
untold
'indescribable' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for untold that I've seen before include "beyond description?" , "Unspoken - inexpressible - uncounted" , "Countless" , "Innumerable - secret" , "Too many to be counted; not narrated" .)