The addition of -ity to an adjective results in a shift of stress to the antepenultimate syllable; that is, words in -ity are stressed on the last syllable before the -ity, even in cases where this syllable is part of another suffix (as in words in -ability and -icity).
adjective, dumber, dumbest. 1. lacking intelligence or good judgment; stupid; dull-witted. 2. lacking the power of speech (offensive when applied to humans): a dumb animal.
Dumb in the sense âlacking the power of speechâ is perceived as insulting when describing humans (but not animals), probably because dumb also means âstupid; dull-witted.â The noun dummy in the sense âperson who lacks the power of speechâ is also perceived as insulting, as are the terms deaf-and-dumb, deaf-mute, and mute.