When something happens unexpectedly, it takes you by surprise because you weren’t prepared for it, like a surprise party or a sudden rainstorm on a sunny day.
The adverb unexpectedly comes from the word unexpected, which means "something that wasn’t anticipated or planned." When something happens unexpectedly, it catches you off guard and can lead to a range of emotions, like surprise, excitement, or even confusion. For example, you might unexpectedly bump into an old friend at the grocery store or receive an unexpected gift in the mail, creating a memorable moment.