ill will, enmity, hostility - the feeling of a hostile person; "he could no longer contain his hostility"

heartburning - intense resentment; "his promotion caused much heartburning among his rivals"

huffishness, sulkiness - a feeling of sulky resentment

grievance, grudge, score - a resentment strong enough to justify retaliation; "holding a grudge"; "settling a score"

enviousness, envy, the green-eyed monster - a feeling of grudging admiration and desire to have something possessed by another