To do something of a questionable and/or of a puzzling nature. Unpredictable, unnatural and of sketchy moral bent.
One great example would be from "Hello Ma Baby" on YouTube "I can see the lipstick on your shirt you deachy bastard" and "I'm sorry that I made you blue, that was a deachy thing to do".
by Grumpus121 June 5, 2009
Get the deachymug.