Coarsen

['kɔːs(ə)n] or ['kɔrsn]

(verb.) make less subtle or refined; 'coarsen one's ideals'.

(verb.) make or become coarse or coarser; 'coarsen the surface'; 'Their minds coarsened'.

Checked by Desmond--From WordNet

(v. t.) To make coarse or vulgar; as, to coarsen one's character.

Edited by Albert