To frisk someone is to search them, usually for weapons. It’s typical for a crime show to portray a police officer frisking a suspect.
The purpose of frisking is to find out if someone is carrying a particular kind of item. The person doing the frisking may be looking for weapons or a recording device. Another meaning of frisk is more light-hearted: “to play in an enthusiastic manner.” Kids running around a playground are frisking. If you say there’s frisking going on in a nearby park, you might want to clarify which meaning you’re indicating.
search as for concealed weapons by running the hands rapidly over the clothing and through the pockets
the act of searching someone for concealed weapons or illegal drugs