This is the 11392nd most frequent French word.
relax
Relax (French): Relaxed; calm; laid-back.
The term 'relax' is used as an adjective to describe someone's state of being relaxed.
Je me sens si relax après ce massage.
I feel so relaxed after this massage.
'Relaxer' is a verb in this case, meaning 'to relax oneself' or 'to rest'.
Tu devrais prendre quelques jours pour te relaxer.
You should take a few days to relax.
Here, 'relax' functions as an adjective describing the desired atmosphere.