Usage patterns
無慈悲な仕打ちmerciless treatment (of someone)
He treated his subordinates mercilessly.
無慈悲に〈動詞〉to do something mercilessly/without pity
The king executed the traitor without mercy.
無慈悲な運命a cruel, pitiless fate
She was tossed about by a cruel fate.
無慈悲な言葉cruel, unfeeling words
He pushed her away with cruel, unfeeling words.