Grunjin Share definition Flag A disparaging word combining the American slang "grunt" (a U.S. Marine) and the Japanese word "gaijin" (foreigner). Grunt + gaijin = Grunjin. Bohannon-san, you Grunjin ...you tellible person...you trow-up rice-su nu-doh on new tatami mat. Grunjin by harry flashman July 12, 2003 0 0 Get merch Get the Grunjin mug. Buy Now — $32.95 See more merch