This is the 2395th most frequent French word.
rire
To laugh.
In this sentence, 'rire' is used as a verb to convey the action of laughing in response to humor.
Il ne peut pas s'empêcher de rire à cette blague.
He can't help but laugh at this joke.
'Rire' is used as a noun here to describe the specific act or sound of laughing.
Son rire contagieux fait sourire tout le monde.
His contagious laugh makes everyone smile.
The verb 'ri' (past tense of 'rire') is used here to indicate the action of laughing during an event.