IPA: /ˈrʌf.nəs/
KK: /ˈrʌf.nəs/
The quality or state of having an uneven or irregular surface; the texture that is not smooth.
The roughness of the stone made it difficult to walk on.
Roughness → It is formed from "rough" (from Old English "ruh", meaning uneven or coarse) and "-ness" (meaning the state or quality of). The word "roughness" refers to the quality of being uneven or coarse.
Think of the word 'rough' to remember that 'roughness' means the quality of being uneven or coarse.