Lewis & Short

rancor, ōris, m. [ranceo, rancens].

  1. I. Lit., a stinking smell or flavor, rankness, rancidity (late Lat.), Pall. 1, 20, 2; 11, 10, 2.
  2. II. Trop., an old grudge, rancor, Hier. Ep. 13, 1.