AITA for calling my Co Worker an Asshole?

Throwaway cause I mostly lurk around reddit and don't interact much and about. So I have this Co Worker named Mathan whom often times called me [F-word]er and Stupid. I generally try to not swear or get Vulgar, but sometimes my irritation and anger can only take so much before I just vent my frustrations through text or other applications. Today is like every other average work day I have. Do work, Hate Mathan, Check up, Hate Mathan, Eat Food, Hate Mathan, Check up 2: The Checking Rises, Hate Mathan, Check up 3: Return of the Checking, Hate Mathan, Go Home, Hate Mathan, Sleep, Repeat. Mathan is nothing less than a lazy guy with friends and married life. And yet he cares little of it and only cares to berate me whenever we work. And I'm at my witts end that I choose to label him as an asshole while he returns to call me [F-word]er and Stupid. So. AITA? I know what will be the verdict so I'm deleting by the half of the month once I do get the verdict. I'm up to take an L cause I've chose to give up early, cause my anger is focused solely on him and my willpower to respond has made it more tiresome to think of what to say, in said response.