Also found in: Thesaurus.
1. Incapable of being expressed; indescribable or unutterable: ineffable joy.
2. Not to be uttered; taboo: the ineffable name of God.
[Middle English, from Old French, from Latin ineffābilis : in-, not; see in-1 + effābilis, utterable (from effārī, to utter : ex-, ex- + fārī, to speak; see bhā- in Indo-European roots).]
in·ef′fa·bil′i·ty, in·ef′fa·ble·ness n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.