You had the opportunity to explain what introversion actually is, but instead this comment is only what it is not. I don't think that's useful if you are actually trying to help the commenter to which you replied.
I spend most of my working day talking to people, and at the end of the work day I'm done with people and need to spend a significant time alone in my head to recharge. I doubt that any of the folks I work with would describe me as an introvert because the nature of my work doesn't allow me to fall into the comfortable isolation I'd prefer. At the same time, I can't have the impact that I do if I was the stereotypical "introvert" engineer which is what makes all the effort worthwhile. The biggest challenge with this is my intolerance for people extends to friends and family after work. A day full of meetings and I can't focus on conversations my wife tries to pull me into and I have zero desire to hang out with any friends. I literally need time alone to recover.
After a long day I tend to zone out and my partner tells me it's like they're talking to a wall.