1. (

• ineffable ,
• unnameable ,
• unspeakable ,
• unutterable

) too sacred to be uttered; "the ineffable name of the Deity" ;

2. (

• indefinable ,
• indescribable ,
• ineffable ,
• unspeakable ,
• untellable ,
• unutterable

) defying expression or description; "indefinable yearnings"; "indescribable beauty"; "ineffable ecstasy"; "inexpressible anguish"; "unspeakable happiness"; "unutterable contempt"; "a thing of untellable splendor" ;

3. (

• unpronounceable ,
• unutterable

) very difficult to pronounce correctly; "an unpronounceable foreign word"; "unutterable consonant clusters" ;