"the ineffable name of the Deity"
"indefinable yearnings"
"indescribable beauty"
"ineffable ecstasy"
"inexpressible anguish"
"unspeakable happiness"
"unutterable contempt"
"a thing of untellable splendor"
"an unpronounceable foreign word"
"unutterable consonant clusters"
You are an unutterable nuisance, but I suppose you must have your own way.
出自: R. Sutcliff
He clasped Frank's hand with a look of unutterable sympathy.
出自: E. Longford