Of sound: without resonance, dull, muffled.

Of a sound or an object producing a sound: Of a deep, dull, or mournful tone. Chiefly poetic.

transferred in various occasionally senses: Made or produced by means of wood; dull or dead, as the sound of wood when struck; relating to or…

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

Of sound: Lacking resonance, ‘thin’. Obsolete.

Of sound: Dull and heavy.

Of a sound: dull, flat, hollow. Now somewhat rare.

Soundless, mute; of a body: without resonance.

Somewhat dead (in various senses).

Not sonorous; giving a dull or muffled sound.

Sounding like a tub when struck; dull or wooden in sound. Of a sound of this quality.

Of the voice or a sound: somewhat muted, indistinct, or breathy.

Of a sound: dull, muffled. Obsolete. rare.

transferred and figurative. Lacking in definiteness or incisiveness; ‘muzzy’; (of the mind, etc.) confused and hazy; (of painting, etc.) lacking in…

Having a dull sound like that of wood when struck.

Of or in reference to physical qualities, as colour or luminosity, sound, taste: Not clear, bright, vivid, or intense; obscure, dim; indistinct…

Not resonant; devoid of resonance.