(a.) Being without remorse; having no pity; hence, destitute of sensibility; cruel; insensible to distress; merciless.

bowelless callous cruel dog-eat-dog flinty griefless hard harsh heartless impenitent implacable inclement inexorable merciless pitiless regretless relentless ruthless savage shameless sorrowless unashamed uncompassionate uncompassioned uncontrite unfeeling unforgiving ungrieving unmerciful unpitiful unpitying unregretful unregretting unrelenting unremitting unremorseful unrepentant unrepining unrueful unsorrowful unsorrowing unsorry unstoppable unsympathetic unsympathizing unyielding without mercy