The acroynm meaning "I Regret To Inform You" that can start any sentence. Especially used by colleges to show that you have been denied admission. But can also be used in social situations to let someone down really easily.
John: So what's going on today, are we going to hang or what?
Sam: Oh, IRTIY we can't hang out. I need to take my dog to the vet, take care of my cousin and spoon feed my half-deaf grandmother. But we can hang out soon.
John: Oh. Then how about tomorrow or something?
Sam: Well IRTIY that I'm no longer your friend. Sorry, bye-bye.