noun
( -es )
Etymology: Middle English deefnesse, from deef deaf + -nesse -ness — more at deaf
: congenital or acquired lack, loss, or impairment of the sense of hearing whether due to defects in (1) the sound-transmitting mechanism, (2) the organ of Corti or auditory nerve, or (3) the interpretative centers of the brain — called also respectively (1) transmission deafness, conduction deafness, or conductive deafness, (2) perceptive deafness or nerve deafness, and (3) central deafness, cortical deafness, or psychic deafness