a dee dah is a person from Sheffield, S Yorkshire, or a supporter of any of the cities football teams
seen them wednesday bastards, they say Dee Dah and Dat instead of thee thaa and that, stoopid bloody dee dah's
an expression of retardedness. its also a lack of knowing an answer. a dee dah is also a person that is just flatout stupid in a funny way
Tim: yo whats this answer yo??
Maeeert: DEE DAH!
Tom: yo you see that girl oveer there?
Chris: dude shes a bumbling dee dah!