Which word means to have force or influence over something?

The word that best means to have force or influence over something is "militate." This term is often used in contexts to indicate that a particular factor or circumstance has a significant bearing or impact on a situation. It suggests an active exertion of influence that sways or affects outcomes, such as policies, decisions, or behaviors.

The other choices do not convey this sense of influence. "Mendicant" refers to someone who lives by begging, "inveterate" describes habits that are firmly established and unlikely to change, and "jocose" pertains to a playful or humorous demeanor. None of these alternatives imply any force or influence over situations or contexts in the way that "militate" does.