merciless

/ˈmʌrsələs/

/ˈmʌsɪlɪs/

Use the adjective merciless to describe someone who acts in a cruel, heartless way. You could accuse your rabbit-hunting brother of being merciless.

Merciless is the antonym, or opposite, of "merciful." If a person shows no mercy or pity, she is merciless. This can describe a cruelly violent person, or it can be more figurative: "The torrential rain was merciless, pouring down on the wedding party as they ran to take cover." The root word is mercy, which comes from the French merci, "reward, gift, or kindness."

Definitions of merciless

1. adjective

   having or showing no mercy
   “the merciless enemy”

   “a merciless critic”

   “gave him a merciless beating”

   synonyms: unmerciful

   bloody

   having or covered with or accompanied by blood

   inclement

   used of persons or behavior; showing no clemency or mercy

   uncompassionate

   lacking compassion or feeling for others

   hard

   dispassionate

   unkind

   lacking kindness

   bowelless, cutthroat, fierce

   ruthless in competition

   mortal

   unrelenting and deadly

   pitiless, remorseless, ruthless, unpitying

   without mercy or pity

   tigerish

   resembling a tiger in fierceness and lack of mercy

   implacable

   incapable of being placated

   antonyms:

   merciful

   showing or giving mercy

   clement

   (used of persons or behavior) inclined to show mercy

   compassionate

   showing or having compassion

   soft

   compassionate and kind; conciliatory

   humane

   marked or motivated by concern with the alleviation of suffering

   kind

   having or showing a tender and considerate and helpful nature; used especially of persons and their behavior