
Oh, the project is CLASSIFIED,
I can't tell you.
The Big Bang Theory Season 10, Episode 19

It's CLASSIFIED.
The Big Bang Theory Season 11, Episode 8

because it's CLASSIFIED
and top secret.
The Big Bang Theory Season 11, Episode 8

That's CLASSIFIED.
The Big Bang Theory Season 2, Episode 22

Oh, I suppose I could redact
the CLASSIFIED parts.
The Big Bang Theory Season 10, Episode 19