Adjective

Used to describe a person with total or profound hearing loss. Many only have mild or partial loss of hearing. Use person with hearing loss, partially deaf. 

Note: Deaf (capitalized) is a social, cultural, and personal identity that is deeply rooted in the Deaf community, while deaf (not capitalized) refers those who have little or no functional hearing. Hard of hearing or HOH is a person whose hearing loss ranges from mild to profound and whose usual means of communication is speech. It is both a medical and a sociological term. Hard of hearing (HOH) and deaf are terms that are used that are not interchangeable. As always, defer to how an individual self-identifies.

Do not use deaf-dumb, deaf-mute. Also do not use hearing impaired, which is a medical diagnosis and using the term implies knowledge of the cause of a person's deafness.

Source

Adapted from UMass Medical and UMassMemorial Health Care’s Diversity + Inclusion, Diversity Toolkit and Connect Hear