Outrageous means shockingly bad, excessive, or completely unacceptable. When something is outrageous, it goes so far beyond what's reasonable that it makes people react with disbelief or anger.

An outrageous price might be $500 for a plain hamburger. An outrageous excuse would be telling your teacher that aliens stole your homework. If someone tells an outrageous lie, it's so extreme that nobody could possibly believe it. When a bully makes an outrageous demand, like insisting everyone hand over their lunch money, the unreasonableness is obvious to everyone.

The word carries a sense of crossing a line. A small mistake isn't outrageous, but cheating on every test for a whole year would be. Forgetting one assignment isn't outrageous, but claiming you don't need to do any homework ever again certainly is.

Sometimes people use outrageous more playfully, like describing an outrageous costume at Halloween that's wildly creative and over-the-top in a fun way. But usually, calling something outrageous means it's gone way too far. When you hear someone say “That's outrageous!” they're expressing that something has violated basic fairness or common sense so badly that it demands attention or consequences.