BOY THAT'S CAP!
Is something you say when you don't want to get caught in a lie, but instead of coming up with a reason to support your lie, you just keep saying "BOY THAT'S CAP!" and get louder with each one, until eventually they just find out that you're full of shit.
Bruce: "DeAndre literally copied my Essay word for word, he even used the same font."
DeAndre: "BOY THAT'S CAP BOY THAT'S CAP THAT'S CAP BOY THAT'S CAP BOY THAT'S CAP BOY THAT'S CAP!"
Bruce: "........."
DeAndre: "BOY THAT'S CAP BOY THAT'S CAP THAT'S CAP BOY THAT'S CAP BOY THAT'S CAP BOY THAT'S CAP!"
Bruce: "........."