1. Free of noise or uproar; or making little if any sound.
2. Characterized by an absence or near absence of agitation or activity.
3. Not showy or obtrusive; SYN. restrained.
4. (Astronomy; of the sun) Characterized by a low level of surface phenomena like sun spots e.g.

ETYM Latin silens, -entis, p. pr. of silere to be silent; akin to Goth. ana-silan.
1. Marked by absence of sound; SYN. soundless, still.
2. Having a frequency below or above the range of human audibility.
3. Not made to sound; SYN. unsounded.
4. (Of film) Having no spoken dialogue and usually no soundtrack.