Mercy

compassionate or kindly forbearance shown toward an offender, an enemy, or other person in one’s power; compassion, pity, or benevolence:
Have mercy on the poor sinner.
the disposition to be compassionate or forbearing:
an adversary wholly without mercy.
the discretionary power of a judge to pardon someone or to mitigate punishment, especially to send to prison rather than invoke the death penalty.
an act of kindness, compassion, or favor:
She has performed countless small mercies for her friends and neighbors.
something that gives evidence of divine favor; blessing:
It was just a mercy we had our seat belts on when it happened.
at the mercy of, entirely in the power of; subject to:
They were at the mercy of their captors.
Also, at one’s mercy.
a female given name.
Contemporary Examples

No mercy or leniency should be granted you or those who were your accomplices in your nefarious enterprise.
What I’d Like to Tell Bernie in Court Burt Ross March 11, 2009

While Mahoney prayed, Rev. Rob Schenck turned his palms to the sky and muttered, “Yes” and “Have mercy” over and over.
Inaugural Freak Show Max Blumenthal January 13, 2009

Right then I knew for certain: there was indeed no mercy in Hell Week.
Navy Seal Training: The Start of Hell Week Marcus Luttrell, Patrick Robinson May 7, 2011

But give the Kingdom credit for its sense of mercy: The lashes will be administered only 50 at a time.
In Defense of Blasphemy Michael Tomasky January 8, 2015

But she is still at the mercy of the judge who sent her to be stoned in the first place.
I Am Outraged! Shohreh Aghdashloo August 2, 2010

Historical Examples

“He has me at his mercy now,” thought Heyst, without particular excitement.
Victory Joseph Conrad

It was awful to Harriett that her father should be ill, lying there at their mercy.
Life and Death of Harriett Frean May Sinclair

But out of the sky came a voice and it cried ‘mercy—mercy to him!’
Operas Every Child Should Know Mary Schell Hoke Bacon

Oh, miss, ain’t it a mercy everybody ain’t so like your own!
Weighed and Wanting George MacDonald

You say you have come as messengers of mercy to us, and as the messengers of the nations.
The Government of God John Taylor

noun (pl) -cies
compassionate treatment of or attitude towards an offender, adversary, etc, who is in one’s power or care; clemency; pity
the power to show mercy: to throw oneself on someone’s mercy
a relieving or welcome occurrence or state of affairs: his death was a mercy after weeks of pain
at the mercy of, in the power of
n.

late 12c., “God’s forgiveness of his creatures’ offenses,” from Old French mercit, merci (9c.) “reward, gift; kindness, grace, pity,” from Latin mercedem (nominative merces) “reward, wages, pay hire” (in Vulgar Latin “favor, pity”), from merx (genitive mercis) “wares, merchandise” (see market (n.)). In Church Latin (6c.) applied to the heavenly reward of those who show kindness to the helpless.

Meaning “disposition to forgive or show compassion” is attested from early 13c. As an interjection, attested from mid-13c. In French largely superseded by miséricorde except as a word of thanks. Seat of mercy “golden covering of the Ark of the Covenant” (1530) is Tyndale’s loan-translation of Luther’s gnadenstuhl, an inexact rendering of Hebrew kapporeth, literally “propitiatory.”

compassion for the miserable. Its object is misery. By the atoning sacrifice of Christ a way is open for the exercise of mercy towards the sons of men, in harmony with the demands of truth and righteousness (Gen. 19:19; Ex. 20:6; 34:6, 7; Ps. 85:10; 86:15, 16). In Christ mercy and truth meet together. Mercy is also a Christian grace (Matt. 5:7; 18:33-35).

see: at the mercy of