ndwtl
An abberviation used in texts, e-mails or social media to mean you're "not down with the lingo," most commonly used when someone uses internet or text slang you are unfamiliar with.
Jack: I just met the President. nbd.
Jill: nbd?
Jack: No big deal. You're apparently ndwtl.
Jill: nbd?
Jack: No big deal. You're apparently ndwtl.