Difference between Unmerciful and Ruthless

UNMERCIFUL vs RUTHLESS: ADJECTIVE

Unconscionable; exorbitant.
Not merciful; not influenced by mercy; unkind; cruel; inhuman; merciless: of persons or things.

Synonyms Unpitying, hard-hearted.
Unmodified or unrestrained by pity; marked by unfaltering rigor; relentless; merciless: as, ruthless severity.
Having no ruth or pity; cruel; pitiless; barbarous; insensible to the miseries of others.

Heartless, Cruel, Unforgiving, Brutal, Relentless, Unpitying, Bowelless, Cutthroat, Tigerish, Fierce, Mortal, Ruthless, Remorseless, Pitiless, Merciless

Callous, Cruel, Vicious, Implacable, Brutish, Savage, Ferocious, Heartless, Bloodthirsty, Brutal, Unpitying, Unmerciful, Pitiless, Remorseless, Merciless

Heartless, Cruel, Unforgiving, Brutal, Relentless, Unpitying, Bowelless, Cutthroat, Tigerish, Fierce, Mortal, Ruthless, Remorseless, Pitiless, Merciless

Callous, Cruel, Vicious, Implacable, Brutish, Savage, Ferocious, Heartless, Bloodthirsty, Brutal, Unpitying, Unmerciful, Pitiless, Remorseless, Merciless

Thank you Great Spirit for your Unmerciful Treatment, I am waiting for you to return.
God, despiteful, proud, boasters, inventors of evil things, disobedient to parents, without understanding, covenant breakers, without natural affection, implacable, unmerciful.
Either these laws are barbarous or the transportation is unjust and unmerciful to those living out of the State.
Undoubtedly to some, the idea of giving so much love to self will seem very cold, hard and unmerciful.
Through the parable of the unmerciful servant, the Savior taught why we must forgive others.
Far be it that we should ever think such an iniquity that God could become unmerciful!
Coston, who was in the habit of prefacing breakfast with prayers of unmerciful length.
Unfortunately some of the priest unmerciful in the continued abuses.
Vicious Rumors offers up an unmerciful audio thrashing on the listener with Razorback Killers.
The dead and disturbed are unmerciful in their revenge!

Thomas Kunz who elevates ruthless to new heights.
For a Ruthless Cultural Criticism of Everything Existing.
We never imagined homeowners could be so ruthless.
Only the ruthless thrive in this uncompromising world.
When will this ruthless suppression of freedom end?
Rockefeller was ruthless when running Standard Oil Company.
The ruthless evil sleazy soulless business man being eaten up by an even more ruthless evil sleazy soulless business man.
When you assume the ruthless option is the strongest, it tends to make you always go for the ruthless option.
Ruthless Records, and I was running Ruthless with Tomika, so I was bridging the gap.
Alistair is said to be ruthless when torturing souls, being so ruthless even the demons fear him.