informal term meaning to calm down and relax?

The informal term for “calm down and relax” in a crossword puzzle could be “chill” or “chill out.”

Few more informal terms for “calm down and relax” that might fit into a crossword puzzle:

Mellow

Unwind

Take a load off

De-stress

Decompress

Cool it

Loosen up

Kick back

Ease off

Settle down

More:

1. Chill out
2. Take it easy
3. Relax, dude
4. Mellow out
5. Unwind
6. Kick back
7. Cool it
8. Ease off
9. Loosen up
10. De-stress
11. Settle down
12. Take a breather
13. Decompress
14. Cool your jets
15. Don’t sweat it