Mansplaining: “This happens when someone that read something on Wikipedia try to explain/argue with someone who has a PhD on the subject.”
That definition would be more accurately fitted to “Dumbsplaining”! Mansplaining is always used to describe a man explaining something to a woman, in a manner regarded as condescending or patronising. Its original use was an ignorant man explaining something to a woman who happened to be an expert on the subject, but today it is used to insult any man explaining anything to a woman whether he’s an expert in the subject or not. I know this is true because it has been Femsplained to me many times.