Something uneven is not smooth or even.
You'll often hear people talk about uneven ground when they mean it's bumpy and hard to walk on. Maybe a sidewalk has been broken up by tree roots over time, making it uneven. Or you might be at a park where the path winds around hills and little valleys, creating an uneven terrain that's fun to hike but tricky to skate on.
Of a surface, not even; covered with raised spots, pits and grooves.
