This is the 480th most frequent Norwegian word.
plutselig
"Plutselig" means "suddenly" in English.
Here, 'plutselig' is an adverb introducing an unexpected event.
Plutselig begynte det å regne kraftig.
Suddenly, it started raining heavily.
In this sentence, 'plutselige' is an adjective modifying 'avgjørelse', describing its unexpected nature.
Hennes plutselige avgjørelse overrasket alle.
Her sudden decision surprised everyone.
Here, 'plutselig' functions as an adverb to describe the manner of the reaction.