Synonyms: unforgiving
Definition: unwilling or unable to forgive or show mercy
Usage: a surly unforgiving old woman
Similar words: revengeful, vengeful, vindictive
Definition: disposed to seek revenge or intended for revenge
Usage: more vindictive than jealous love- Shakespeare; punishments...essentially vindictive in their nature- M.R.Cohen
Synonyms: inexorable, grim, unrelenting, relentless, unappeasable, unforgiving, stern
Definition: not to be placated or appeased or moved by entreaty
Usage: grim determination; grim necessity; Russia's final hour, it seemed, approached with inexorable certainty; relentless persecution; the stern demands of parenthood