Expatiate is a verb that means to move freely or wander.

The Latin word exspatiari (ex POT ee air ay) which means ‘to wander from a course’ is where our word of the day has wandered. A person can expatiate on foot by walking away from a path or they can do it with words by digressing from the topic, for example: I liked Rhonda’s speech about the beauty of public parks, but I didn’t care for the part where she began to expatiate into a rant about tax policy. Personally, I don’t care for people who wander off into political matters and away from the topic at hand.