The Latin prefix “pro-” means “forward,” and “clivus” means “slope,” but instead of denoting a physical forward incline, this word refers to behaviors. For someone to have a proclivity for something means that they are strongly inclined to do that thing. The word is often used in a sense of being predisposed toward negative traits or behaviors, but it’s also used in the positive. A child might show an early proclivity for music or art, while someone else might be critiqued for their proclivity toward tardiness.