hey here you are a few words
Vamos a tomar un "DESCANSO"
Podríamos ir a "RELAJARNOS" un momento antes del examen.
young people from Mexico says "Vamos a tomarnos un "BREAK(descanso)"

The word for relax in spanish is "relajar" (thats the dictionary version) you can use the words "descansar","desestresarse", "distensionarse",, that depends of the context,,
desestresarse = we use this word when we are under stress,,,
descansar-=means rest
distensionarse= we use this word when we are under stress, you can use this word too when youre talking about sporting activities for example in the sentense "you need to relax your muscles"="tu necesitas relajar ó distensionar tus mùsculos"

depends the context ur looking for .. heres 1 example ..
" hey.. relax, aint that bad " --> " hey .. relajate , no es tan malo"

dunno if this is what ur looking for but i hope it helps .. good luck !

In Costa Rica, relax means tranquilo.

well the word Relax have a different uses for the colombian spanish check it:

Relax is means.. to take control about something
or
to calm down(situation, myself)
to take it easy(when you got a bad situation)
to take a break(take a nap, or make an another hobbie)
it´s a synonym for Chill out just like this... Relax!

In Spain we use "relax" word too. But there are too many (because is a concept that the Spaniards do much use). You can say: descansar, reposar, relajar, "me voy a echar la siesta", "me voy a tomar el café", "me salgo a fumar el cigarro" (this two last very used at work)...

if you want say relax to someone Just say" TRANQUILIZATE" =) or "TRANQUILO" for guys, "TRANQUILA" for girls and "TRANQUILOS" for a lot of people