From Wiktionary, the free dictionary
From dump + -s- + -ville.
Dumpsville
- (slang) The notional location of a person who has been dumped, or jilted by a lover.
2012, Amy Sohn, Run Catch Kiss, page 209:Sara was right. I'd botched everything up. My faux fuck would fuck me over. My not cheating and telling. Welcome to Dumpsville. Population: me.
