A cross-country runner is an athlete who competes in long-distance running events, usually on a course that covers terrain such as grass, mud, hills, and other natural obstacles. The two crossword solutions for this term are 'HARRIER' and 'SKI'. A HARRIER is a type of cross-country runner who typically runs on trails or paths, while a SKI runner is a type of cross-country runner who competes on snow-covered terrain.