I honestly think the problem is not the meaning of the word itself, but the context where it's used.
e.g.
- "Farming" can be used in MOBAs as well as in any single player JRPG, and in both cases can be substituted by "grinding". Two different words, same identical meaning, but the context they're used in changes everything; they also come from different cultural contexts, as farming is mostly used in western communities, while grinding comes from eastern ones, and is usually applied to their MMORPGs which require hours and hours spent on killing the same enemy over and over and over and so on...
- Newbie and Professional can be used in anything else not related to gaming; however, in gaming, they usually assume the form of "noob" and "pro/pr0" (that 0 in regard to the same rules that apply for élite/1337, I suppose), which nowadays are used more for mocking rather than for distinguishing someone good from someone new/inexperienced. I, for one, don't see noobs or pros, I see players. This is because, at least IMO, the words themselves have lost their meaning with time, used by the people who knew their true one and literally abused by the rest of the community, which just say those words because they've seen someone else say them...
Otherwise, it's just a way to communicate easier and faster, most of the times, as you minimize the time you spend writing by doing that.
e.g.
- "Farming" can mean "Gain gold until you can afford [item_name_here]", or "Gain experience until you are level [level_value_here]"; 1 word versus potentially 7 to 10 words.
- (strictly MOBA related) "ss", short for "miss", short for "Enemies missing in [lane_position] lane"; 2 letters versus 5 words.
Being widely accepted words amongst the community makes them a nice surrogate for proper language; it allows you to chat less and play more, play faster and play more reactively. Writing a complete sentence in proper english can take time, and even so, not everyone knows english/american perfectly; it's also a easier way to understand each other when language knowledge fails or isn't enough, as you're not forcing someone to go take up an english-[my language] dictionary every single time you write something 😛
And to prove the point about language knowledge up there, just look at me. I'm italian, I bet there are some grammar errors in what I've written, although I deem myself pretty much english-capable.