What's the "een" in Halloween?
masc. proper name, from the family name, from the region of the Clyde River in Scotland (see Clydesdale). Most popular in U.S. for boys c.1890-1910, falling off rapidly thereafter, hence probably its use in 1940s teenager slang for "a square, one not versed in popular music or culture."
A person who does not appreciate the current music, culture, etc; square (1940s+ Students)