1) Abrade 2) Alter 3) Become more vulgar 4) Change 5) Get rough 6) Get rougher 7) Get tough 8) Make crude 9) Make harsh 10) Make less subtle or refined 11) Make more crude 12) Make rough 13) Make rougher 14) Make vulgar 15) Modify 16) Rough up 17) Scratch 18) To become coarse 19) To make coarse 20) To make or become coarse 
• (v. t.) To make coarse or vulgar; as, to coarsen one`s character.
Coars'en (kōrs''n) transitive verb To make coarse or vulgar; as, to coarsen one's character. [ R.] Graham. 
[v] - make or become coarse or coarser 2. [v] - make less subtle or refined
verb make less subtle or refined; `coarsen one`s ideals`
to make or become coarse.