transferred from sight to sound. Obsolete.

Of sound, a resonant instrument, a voice: Not clear and sharp; dead, dull. Also in combinations, as flat-sounding, flat-vowelled.

Not modulated.

Not modulated; without vocal modulation.

Having no distinctive quality; (a) of sound: without modulation or expression; (b) of colour: dull.

void of inflection or modulation.

Of the voice: lacking timbre; having no distinctive quality or characteristic; without depth, intensity, or variation; monotonic.