merciless
adj. B2 Upper Intermediate US //ˈmɝsəɫəs// UK //mˈɜːsɪləs// mer·ci·less
adj. showing no kindness or pity toward someone. You use this to describe a person or thing that is very cruel and does not stop.
adj. showing no compassion or forgiveness; cruel and harsh in nature. Often used to describe people in power or extreme environmental conditions.
The merciless sun beat down on the desert travelers.
The dictator was merciless toward anyone who dared to speak out against his government.
The critics were merciless in their reviews, dissecting every minor flaw in the performance until the young actor's confidence was completely shattered.
From Middle English merciles, mercyles, equivalent to mercy + -less.
Usage
Typically used attributively before a noun or predicatively after a linking verb like 'be' or 'seem'.