Pitiless means showing absolutely no pity, mercy, or compassion. A pitiless person feels no sympathy for others' suffering and won't soften their actions even when someone is clearly hurting or struggling.

Think of a pitiless drill sergeant in a movie who pushes soldiers through brutal training without caring about their exhaustion or pain. Or imagine a pitiless villain in a story who continues their cruel plan even when people beg them to stop. The word suggests a hardness of heart, a complete absence of the natural sympathy most people feel when they see someone in trouble.

Nature can be pitiless too. A pitiless desert sun beats down with no relief, and a pitiless winter storm rages without regard for anyone caught in it. When we describe nature this way, we're emphasizing how it follows its own rules without any concern for human comfort or safety.

Someone pitiless has removed or locked away their capacity for mercy. When you hear this word, you're encountering something or someone cold, harsh, and unforgiving.