expression, noun
muffled voice; thick voice
Describes a voice that sounds unclear, as if coming from behind something, often due to a mask, a closed door, or emotional suppression.
マスク越しのこもった声で話す。
Speak in a muffled voice through a mask.
隣の部屋からこもった声が聞こえた。
I heard a muffled voice from the next room.
Similar meaning, but くぐもった声 often implies a lower, more indistinct sound, while こもった声 can also suggest emotional thickness or being held back.
From the verb こもる (to be shut in, to be muffled) in its past attributive form modifying 声 (voice).