This is the 3258th most frequent French word.
soudain
Sudden.
In this sentence, 'soudain' is an adverb describing the unexpected and quick manner in which the action occurred.
Il est apparu soudain derrière moi.
He suddenly appeared behind me.
Here, 'soudaine' is used as an adjective to qualify the noun 'envie' (urge), highlighting its abruptness.
Elle a eu une soudaine envie de partir.
She had a sudden urge to leave.
In this example, 'soudain' functions as an adverb modifying the entire sentence to indicate an abrupt change in condition.