1.
unevenness; bumps and dips; irregularity of surface
Physical roughness or variation in height on a surface. Describes terrain, roads, or textures that are not flat or smooth.
凹凸 is a noun formed from 凹 (concave) and 凸 (convex). The two characters visually represent their meanings — 凹 looks indented and 凸 looks protruding.
Common collocations
Usage
Often appears in descriptions of roads, terrain, and materials. Can also be used figuratively to describe an uneven situation, though the literal usage is far more common.