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.
Smart dumb refuses to commit to either one state or the other. Smart dumb, for instance, incorporates elements of camp but refuses to be camp enough to actually be camp. Dumb vs. smart is not a rehash of hip vs. square. Dumb is both hip and square.