1、take a nap: to sleep (usually for a short time)
also: take a snooze
eg. Every afternoon my old grandpa takes a nap on his recliner for an hour.
2、take a break: to rest by stopping work or play
also: take a breather
eg. We've been having two classes this morning. Let's take a break.
3、have free time: to have little or no work to do, to have extra time
also: have time on one's hands, have time to kill
eg. Whenever Miss Green has free time, she goes to the garden and look after the flowers.
4、pass the time: to spend time (usually relaxing)
also: while away
eg. Our flight was delayed on departure, so we passed the time playing cards.
5、loosen up: to become more relaxed, to become informal
also: let one's hair down
eg. Why are you always so serious? You should try to loosen up a little.
6、take it easy: to relax, remain calm, not to work so hard
eg. Take it easy and tell me what has happened.
7、daydream: to think about something not related to what is happening at that moment
eg. Tommy sat at his desk and daydreamed about playing with his dog in the garden.