Quiet, calm, and composed; little noise or activity. When used of a person, describes someone who is calm and reserved.
この地区は夜になると物静かになる。
This neighborhood becomes very quiet at night.
彼女は物静かな人で、あまり自己主張をしない。
She is a quiet person who doesn't assert herself much.
図書館の中は物静かで勉強に集中できた。
The library was quiet, so I was able to concentrate on studying.