A filmgoer is someone who goes to the cinema to watch films, especially as a habit — not one rainy afternoon, but a person who turns up. It is a rather British way of putting it; Americans almost always say moviegoer. Both sound a little like newspaper talk; friends are more likely to say "people who go to the movies" or "a movie fan". Filmgoer stresses the going-out, the seat in the dark, not just watching at home. You can also meet churchgoer, theatregoer, concertgoer — same build: a person who goes to that kind of place.