Boner
来自Big Physics
mid 19th century (originally school slang, in the now obsolete sense ‘a blow to a bony part of the body’): from bone or (in boner (sense 2)) bonehead, + -er1.
wiktionary
From bone + -er.
etymonline
boner (n.)
"blunder," 1912, baseball slang, probably from bonehead. Meaning "erect penis" is 1950s, from earlier bone-on (1940s), probably a variation (with connecting notion of "hardness") of hard-on (1893).
