Look at the employee handbook, if any, and read the policy on harassment. Consider sending your boss a letter or email listing his cuss words and any policy and ask him to comply. It is nice to go to him first out of courtesy if it works. Then, if he does not stop, go over his head to his boss with a copy of your original notice to your boss and ask for help. Keep a journal to track his improper actions and words as well as any complaints you have made as it may be good evidence later. If it still does not stop, consider filing a claim with the the Federal Equal Employment Opportunity Commission or your state counterpart agency, if any. Evaluate the type of cussing involved, such as religious, race, sexual, or vulgar as that may affect how your claim is filed. If you are stressed out by it, consider going on a short medical leave and get some medication for it, and have the doctor allow your return in writing on condition that the improper actions cease. That would further document your suffering and put the pressure on the company to act.