To grab another person from the back of the head and slam their face on the edge of an object. Like a shelf, table edge, or protruding ledge of some sort.
Person1: "Did you hear about the fight today?"
Person2: "Yeah I heard the Brad delwonked some guy off a bookshelf then a table."
Pounding of someone's face off the edge of a large object, such as a table. Usually done forcefully after a long argument regarding significant others and cheating.
Ben: Dude! Did you hear Balbs got delwonked?
Gary: Yeah, what's up with that?
Ben: Well I guess she was cheating on Chris and he found out, so he delwonked her off the table.