A paramotor is a 2- or 4-stroke engine with a propeller, frame, harness and connection points for a paragliding wing. Its purpose is to launch a person into the sky, like so:
Long story short, it’s a lawnmower engine with a propeller, seat and wing attached. They fly about 20-25 mph, generally around 500 feet above the ground or so. You can go faster or slower, higher or lower, but that’s the gist of it.
The U.S. Powered Paragliding Association has more (and actually serious) information at www.usppa.org/about-ppg.