I didn't even know "whimsy" was a word. It's not a word that's known/used here. A "whimsical" person, to me, is someone who "takes notions." One week they're into meditation and the next they're singing death metal. But again, it's not a word that's really used.

Qualcuno che non e' serio. For example, you would not want to put a whimsical person in charge of a project, unless it was something non-serious, such as I don't know, a group outing where doing fun things and letting go of work etc. was the main goal.

In American culture(well, at least at my school) people accept weird or "whimsy" people- only certain ones though. Most people don't like those who act childish when they're supposed to be at least somewhat mature. In my opinion, most Americans are considered "weird" to foreigners because they're loud but friendly. It depends on how you define the word "whimsy." Who's considered "whimsy" where you live? The people who joke around a lot or the ones that are super cringey?