noun
silly person; dope; dumb-bunny
Affectionate or teasing term for someone acting foolishly; often used playfully rather than as a harsh insult.
また忘れ物したの？おばかさんだね。
You forgot something again? You're such a silly goose.
彼はいつも変なことばかり言うおばかさんだ。
He's a dope who always says weird things.
ばか is a more direct and potentially harsher 'fool' or 'idiot'. おばかさん softens it with the polite prefix お and the honorific さん, making it sound more affectionate or teasing.
Derived from ばか (fool) with the polite prefix お and the honorific suffix さん, giving it a softer, more playful tone.