piedpilkado

A triple build, and every piece is one you know. Piedo is foot, pilko is ball, and -ad- turns a root into the activity of doing it. So piedpilko is the ball or the game as a thing, and piedpilkado is the playing of it - which is why the frequency list has the longer form. If a sentence is about the sport as an activity, the -ad- is doing real work; if it is about a match, piedpilka matĉo is what you want.

The catch: most speakers say futbalo. There are two words here and they are not equal in the wild. Futbalo is the international borrowing, it is what PIV leads with, it is what the Esperanto national football team calls itself (Esperanta futbala teamo), and it is what you will hear in a bar. Piedpilko and piedpilkado are the home-built alternatives, favoured by speakers who prefer Esperanto to assemble words rather than import them, and they are perfectly correct and widely understood. Some writers use the pair to make a distinction: futbalo for association football specifically, piedpilko for the broader family that includes rugby and the American and Australian codes. Learn both, use whichever fits the room, and do not let anybody tell you one is an error.

Why the argument exists at all. This is la bona lingvo in miniature - a long-running preference among some Esperantists for building from existing roots instead of borrowing a new one, on the grounds that a learner who knows piedo and pilko gets piedpilkado free while futbalo has to be memorised. Compounding explains the machinery. The counter-argument is that futbalo is what the world already says, and the international word is easier for the Brazilian and the Pole than the transparent one. Both positions are held by fluent, thoughtful people, which is the tell that neither is silly.