1. slang Foolish nonsense or untruthful rubbish. From Yiddish. Why, I've never heard such shmegeggy in my entire life! Quit filling the kids' heads with that shmegeggy about the dybbuk, Jerry. They're going to have nightmares for weeks!
2. slang An impudent, ignorant, oafish person. From Yiddish. I just don't understand why she ever married a shmegeggy like him. Jeff is managing the project? That shmegeggy couldn't manage his own sock drawer.