upperclassman

[ uhp-er-klas-muh n, -klahs- ]
/ ˈʌp ərˈklæs mən, -ˈklɑs- /

noun, plural up·per·class·men.

a junior or senior in a secondary school or college.

Origin of upperclassman

An Americanism dating back to 1870–75; upper1 + class + -man