hypacusis hyp·a·cu·sis (hĭp'ə-k&oomacr;'sĭs, -ky&oomacr;'-, hī'pə-) or hy·po·a·cu·sis (hī'pō-ə-) n. A hearing impairment associated with a deficiency in the peripheral neurosensory or conductive organs of hearing.