You call HR first. Let them know the type of environment they have created for you. HOSTILE! Let hr know you didnt say these things. And if you didn't, there were no witnesses, but your manager is threatening you with HR. So you figured you'd give them a call first. because technically if you did call this guy a name, it is the managers obligation and duty to report it iimmediately. So there Gonna side with you. and if your manager fires you for going to HR. that is a serious lawsuit. collect unemployment until your lawyer settles the case. They cant fire you. He created a hostile work environment for you. With that he said she said stuff.