This is the 7092nd most frequent Spanish word.
fas
"Fas" is an archaic or literary term in Spanish meaning "divine law" or "what is morally right."
Used as a colloquial noun meaning 'in an instant' or 'quickly'.
En un fas, resolvimos todos los problemas.
In a flash, we solved all the problems.
Here, 'fas' refers to the speed or carelessness in dealing with something.
No me gusta el fas con que trató ese asunto.
I do not like the haste with which he treated that matter.
The word 'fas' is used to describe the quickness or agility in action.