1. unwilling or unable to forgive or show mercy

- a surly unforgiving old woman

Similar word(s): revengeful, vengeful, vindictive

2. not relenting; having no pity; not being or becoming lenient, mild, gentle, or merciful; unyielding.

Similar word(s): implacable, grim, inexorable, relentless, stern, unappeasable, unrelenting

Sentences with unforgiving as an adjective:

- The electorate was in an unforgiving mood.

- The unforgiving Arctic climate makes short work of the unprepared.