Green’s Dictionary of Slang

lute n.2

[abbr.]

(US) a Lutheran.

Lahey-Hogan As I Remember It 131: The Boslers were Lutherans and were supposed to be very religious. The Barnes were Catholic and that was a very great bone of contention. On the school ground they would yell, ‘Catlickers’ and the other side would call, ‘Lutes who follow a crazy Catholic monk who never did know anything.’ [HDAS].
‘Student Life @ PLU’ Pacific Lutheran University 🌐 LuteLingo: Lute(s) – 1. One who shares the pride and commitment that comes from being a member of the Pacific Lutheran University community; ‘I am a LUTE!’ 2. Any of PLU’s outstanding athletic teams; ‘Go LUTES!’.