1. (sometimes lowercase) Slang. most wonderful or exciting: a rock band that was regarded as Endsville in the late fifties.
2. (sometimes lowercase) Slang. (of a location, circumstance, etc.) most isolated or undesirable.
She responded by flinging her arms around his neck. “Curtie, it’ll be endsville!” –Arthur Hailey,Hotel, 1965 Here is the Twinkies and Thunderbird generation for which ”endsville” was the super superlative and stealing hubcaps was the thrill of the night, until the fuzz came. –Alvin Klein,”Darien’s ‘Grease’ Catches the Mood of a Decade,” New York Times, June 10, 1990
Endsville is an extension of the slang expression the end, meaning “the ultimate; the utmost of good or bad.” It entered English in the 1950s.