a. [ OF. rancuros. ] Full of rancor; evincing, or caused by, rancor; deeply malignant; implacably spiteful or malicious; intensely virulent. [ 1913 Webster ]
So flamed his eyes with rage and rancorous ire. Spenser. [ 1913 Webster ]
adv. In a rancorous manner. [ 1913 Webster ]