This is the 5761st most frequent Catalan word.
fous
"Fous" in Catalan means "pits" or "holes."
In this sentence, 'fous' is used as a noun referring to 'pits' or 'holes' in the ground.
Vaig veure uns fous al bosc ahir.
I saw some pits in the forest yesterday.
Here, 'fou' is an adjective meaning 'crazy' or 'irrational' linked to a person's behavior.
No siguis tan fou, pensa bé abans d'actuar.
Don't be so crazy, think well before acting.
In this expression, 'fosa' is an adverb derived from 'fou', implying looseness or an uncontrolled natural movement.