gump comes from a Scandinavian word for buttocks or rump and is low cant for a complete nitwit.
Thank you, tsuwm. Reckon it was appropriate, then. I must be about the only person who didn't like that movie. Maybe it's just that I don't like Tom Hanks--I didn't like Sleepless in Seattle, either. Though maybe it's that I'm a bit hypersensitive to insults to people who are 'different'. I HATED The Waterboy!