The term professionalism originated from a business setting referring to the way a professional should conduct themselves. Behavior should be appropriate for the situation, usually mature and proper, attire should be business or business casual, and the person in general should be well kempt.
This term somehow trickled down into the colleges and universities and has taken on a whole new meaning due to its new non-professional environment.
Professionalism is a term is used by many professors who think that you are not worth their time or are lazy and tenured. Professors use this term for their own amusement or simply to watch their students gawk as they are blatantly insulted.
Its uses are, but not limited to, belittling a student or class, insulting students by suggesting they are too ____ , suggesting that students are asking stupid questions, the student is just wasting their time, or to simply usher the student out of their office with no other reason.
"Where is your professionalism! You don't know what you're talking about. Now get out of my office!" -Lazy professor
"I tried to ask him a question about the course but he yelled at me for wearing pajama pants. Saying it was a lack of professionalism or something and wouldn't answer my question." -General Student
"Oh I hate that professor.. I take good notes but I don't understand what he's talking about. He always makes me feel stupid when I try to ask a question- He just goes on and on about this professionalism crap and I don't ever get an answer to my question!" - General Student