Characterized by an absence or near absence of agitation or activity.
Free of noise or uproar; or making little if any sound.
Not showy or obtrusive.
(Of a body of water) free from disturbance by heavy waves.
Of the sun characterized by a low level of surface phenomena like sunspots e.g.
A period of calm weather.
A disposition free from stress or emotion.
Become quiet or quieter.
With little or no activity or no agitation (`quiet' is a nonstandard variant for `quietly')