dumb

before 1000; Old English; cognate with Old Norse dumbr, Gothic dumbs, Old Saxon dumb, Old High German tump, German dumm

Dumb in the sense “lacking the power of speech” is perceived as insulting when describing humans (but not animals), probably because dumb also means “stupid; dull-witted.” The noun dummy in the sense “person who lacks the power of speech” is also perceived as insulting, as are the terms deaf-and-dumb, deaf-mute, and mute. The adjective hearing-impaired is acceptable though not the term of choice, partly because it lacks directness. The preferred term is deaf, which makes no reference to an inability to speak or communicate; the capitalized Deaf signals membership in this community.