This is the 73rd most frequent French word.
faut
"Faut" means "is necessary" or "must."
'Il faut' implies an obligation, meaning 'it is necessary to' or 'one must'.
Il faut écouter les instructions.
One must listen to the instructions.
'Il faut' here indicates a necessity not regarding an action but a requirement.
Pour réussir, il faut du courage.
To succeed, one needs courage.
'Il faut que' is often used to express that something is necessary, followed by a subjunctive verb for specific requirements.