Commonly used by bogans and Australian Aboriginies to describe something cool or extraordinary. Possibly originated from a lazy pronunciation of "Does alright aye".
People who say dardy that aren't making fun of someone else who says dardy should be avoided if possible and definetaly not befriended.
This day's been pretty dardy, I stole some guys thongs on the train ride home.
Rebecca: Hey, Hardy's name is Hardy Douglas!
Clara: You know what would be cool? What if his name was DARDY HOUGLAS??
Rebecca: DARDY!!
Me: Woah, who's Dardy? Are we still talking about Hardy?
Rebecca: Hardy? Who's HARDY?? The only person I was talking about was DARDY!
Hardy: OH MY GOD SHUT UP