This is the 9970th most frequent Japanese word.
越野
"越野" means "cross-country" in English.
In this context, '越野' describes the travel as involving crossing over natural terrain or varied landscapes.
越野旅行は体力が必要です。
Cross-country travel requires physical endurance.
In this sentence, '越野' is used as an adjective to describe the marathon, indicating its nature as taking place across varied terrain.
私は越野マラソンに参加することを決めました。
I decided to participate in a cross-country marathon.
Here, '越野' acts as a descriptor understood to mean 'suitable for cross-country or off-road conditions' when describing the car.