See https://en.wikipedia.org/wiki/Political_correctness
My definition is that, as used nowadays, "political correctness" means an excessive, artificial, and affected attention to using newly-coined neutral or euphemistic terminology, instead of older terminology that is thought to reflect race, gender, or other kinds of discrimination.
Here's an example. In a forum posting elsewhere, in a discussion of a financial product someone was thinking of buying, I said:
"I don't think that this insurance company is trying to gyp you."
Another forum member chided me. The word "gyp" means "to cheat or swindle," but it is a prejudiced reference to "gypsies"--an informal word for the Romani people. The idea behind it is that gypsies are cheaters and swindlers. Now, personally, I simply grew up hearing that word. I never thought of "gypsies" when I used "gyp." I used it quite innocently. However, it is now considered a politically incorrect term.
I could have done one of two things. I could have apologized and edited my posting, replacing "gyp" with the word "cheat," which is what I did.
Or I could have gotten angry and said "It's a perfectly good word. I didn't mean anything offensive by it. I refuse to bow to any silly 'political correctness.'"
Tony, since your English is advanced, you might be able to understand humor about political correctness. Political correctness is frequently mocked because sometimes it seems they go to such ridiculous lengths to avoid offending anyone. Here are a couple of comedy skits making fun of politically correct terms.
https://www.youtube.com/watch?v=g0PZ31SF7rY Blue Collar TV Politically Correct Fairy Tales With Larry The Cable Guy
https://www.youtube.com/watch?v=eidz4JD7F80 Larry the Cable Guy-"Politically Correct" Christmas Story