Particularly disgusting, unattractive, or undesirable.
"I had some delicious mushroom soup last night!"
"Ew, mushrooms are dag nasty."
"Did you see that girl at the club last night?"
"She was hot, but her friends were all dag nasty."
1. a positive adjective used usually to describe something of indescribable measure by comparing it to the particular style of music that used chords D-A-G and the atmosphere that surrounded it.
originated from the 1970's era when D-A-G were popular chords used in rock songs by such bands as the velvet underground.
2. a hardcore band formed in 1985.
"that song is dag nasty."
"this club is dag nasty."