Meaning : Happening unexpectedly.
Example :
Suddenly she felt a sharp pain in her side.
Synonyms : all of a sudden, of a sudden
Meaning : On impulse. Without premeditation.
Example :
He decided to go to Chicago on the spur of the moment.
He made up his mind suddenly.
Synonyms : on the spur of the moment
Suddenly meaning in Bengali (Bangla).