Webster's Revised Unabridged Dictionary · 1913

deafening

deafening , noun

The act or process of rendering impervious to sound, as a floor or wall; also, the material with which the spaces are filled in this process; pugging; sound insulation.

deafening , adjective

extremely loud; so loud as to cause deafness; as, a disco with rock music played at a deafening volume.