noun, noun which may take the genitive case particle 'no'
silence; no sound
Refers to a state of complete silence or absence of sound. Often used in technical or descriptive contexts.
部屋の中は無音だった。
The room was completely silent.
無音の
I meditate in a silent space.
音 means there is sound, while 無音 means there is no sound at all, i.e. silence.
無音 means the absence of sound in general (e.g. a silent video), while 無言 specifically refers to a person not speaking.
Compound of 無 (mu, 'without') and 音 (on, 'sound'). The exact historical derivation is uncertain, but the meaning is transparent from its components.