showing no sympathy or kind treatment 毫不怜悯的；无情的；残忍的 a merciless killer/attack 无情的杀手／攻击 the merciless heat of the sun 太阳的酷热 She was subjected to the merciless criticism of her opponents. 她遭到了对手的无情批评。 It brought relief from the merciless summer heat. 它可以让人们摆脱夏日的酷热。