1) Change surface 2) Grow less genteel 3) Make less smooth 4) Make more coarse 5) Make rough or rougher 6) To become rough 7) To make rough Found on https://www.crosswordclues.com/clue/roughen
Rough'en transitive verb [ imperfect & past participle Roughened ; present participle & verbal noun Roughening .] [ From Rough .] To make rough. Found on http://www.encyclo.co.uk/webster/R/96