rancor, ōris, m. [ranceo, rancens].
I Lit., a stinking smell or flavor , rankness , rancidity (late Lat.), Pall. 1, 20, 2; 11, 10, 2. —
II Trop., an old grudge , rancor , Hier. Ep. 13, 1.
·noun The deepest malignity or spite; deep-seated enmity or malice; inveterate hatred. ...
Webster's Dictionary of the English Language