Legwork is the hard, often boring work you have to do in order to get something done — walking around, knocking on doors, making calls, checking facts, going from place to place. A reporter does legwork to find a story; a student does it to gather names for a project. The picture behind the word is your legs: someone had to go out and move. Today it also covers sitting on the phone or searching through papers, as long as it is the slow, necessary grind, not the clever idea at the end. It is informal, a little journalistic, and uncountable: we say “a lot of legwork,” not “many legworks.” Though actually, it does not mean sport or training your legs. Running in the park is not legwork unless it is part of the job.