This is the 427th most frequent Chinese word.
安
"安" means "peace," "safe," or "calm."
In this sentence, '安静' (ānjìng) means 'quiet' or 'to be quiet', and the character '安' conveys a sense of peace or calmness.
安静地听老师讲解。
Listen quietly to the teacher's explanation.
Here, '安全' (ānquán) translates to 'safe' or 'safety', with '安' indicating safety or security.
我们住在一个非常安全的社区。
We live in a very safe community.
In this sentence, '平安' (píng'ān) means 'peaceful' or 'safe', and '安' contributes to the meaning of being at peace or free from trouble.