A retard. Someone mentally challenged.
Look at that dernt! He can barely grunt what with all that drooling he's doing!
by Vamier Stryder June 09, 2005
A sound effect used to describe a unpleasant occurance or appearance etc. Much like the sound of a foghorn.
Someone extremely hungover walks into the room and the only way to describe them is simply "dernt".
by Boyle265 January 14, 2009