Obvious Jew
An OJ is a Jew so obvious, they might as well be shouting it. They have names so Jewish, it’s like they were born with a Hebrew dictionary. Don’t go around tagging every Daniel or Leah unless you're 100% sure they're actually Jewish.
'Daniel? That's an OJ. You can't miss it.'
'Rachel? That's a real OJ. No need to ask.'
'Ezra? That's an OJ. He's got the name to prove it.'