Unpitying is a related term of relentless.
As adjectives the difference between unpitying and relentless
is that unpitying is not feeling or showing pity while relentless is unrelenting or unyielding in severity.
relentless
English
Adjective
(
en adjective)
Unrelenting or unyielding in severity
Unremitting, steady and persistent
Derived terms
* relentlessness