One of the mysteries of the English language finally explained.
A person who engages in some activity (only) on a Saturday night; specifically a person who goes out socially on a Saturday night.
Late 19th century; earliest use found in Hull Packet. From Saturday + -nighter, after Saturday night.
Saturday nighter/ˌsatədi ˈnʌɪtə//ˌsatədeɪ ˈnʌɪtə/
In this article we explore how to impress employers with a spot-on CV.