Simple Definition:

A psychopath is a person who has a mental disorder [a condition that affects a person’s thoughts, emotions, and behavior] characterized by a lack of empathy [ability to understand other people’s feelings and desires] and a tendency to manipulate others for personal gain. For example, a psychopath may appear charming and friendly, but they may also lie, deceive, and exploit others without feeling remorse.

Very Simple Definition:

A psychopath is someone who doesn’t care about other people’s feelings and may use them for their own benefit. For example, a psychopath may pretend to be nice to get what they want, even if it hurts others.