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.

In a quiet manner

The quality or state of being quiet; tranquillity

1. To cause to be quiet; calm
2. To make secure by freeing from dispute or question
3. To become quiet — usually used with down