Deliberately means on purpose. For example, you may have noticed how the schoolyard bully deliberately chose to pick on the smallest kids at recess.
The adverb deliberately originates from the Latin word deliberatus, meaning "resolved upon, determined." Used to describe an action made intentionally, it can also mean doing something in a careful, thoughtful manner. You probably cringed when the pitcher deliberately hurled the ball into the star batter's leg so he would walk rather than hitting another home run. Or perhaps you witnessed a college professor stroking his beard deliberately in response to a classmate's challenging question.