The term means: "Dumb Ass Dog." This refers to a dog that is getting on a person's nerves and because you refer to him as a "D.A.D." rather than calling him a dumbass, it remains a unsuspected, preferential acronym of choice. This slang was created by Bluford and Yogi from the Big V.A.. Rest in peace my people.
Hey Yogi boy ( dachshund hound ), you are one motherf@$*^# big D.A.D.!!! Yea, Yea, Yea!!!
A public safey radio operator. They are everywhere. They don't seem to have common sense!!
Cop: Can you check one by name and D.O.B.?
D.A.D.: Go ahead
Cop: Teresa Blow 01-10-1910
D.A.D.: Can you spell Teresa?
Cop: There are only two ways! Figure it out D.A.D.!!