Yes, you certainly can. Words such as beautiful, pretty, good-looking and handsome can be seen a reasonably objective assessments of someone's appearance. By contrast, 'gorgeous' often has a more sensual connotation. For example, if you describe food as gorgeous, it smells wonderful and tastes absolutely delicious. A gorgeous dress makes you want to wear it. If it's a gorgeous day, you don't want to stay indoors - you want to go to the beach and enjoy it. So, as Paul says, if you say that someone is gorgeous, it may suggest that you find them sexually attractive. That's why a woman, or a gay man, might describe a man as 'gorgeous', but a straight man wouldn't. Likewise, a woman can describe a baby or child as gorgeous, but it would sound very creepy if a man were to do so.

You can say it, but it has a stronger meaning than just saying you think a man is nice looking. Its more like you think the man is really sexually attractive. If you say 'that man is gorgeous' it is stronger than saying 'that man is handsome'. Heterosexual men wouldn't say another man is 'gorgeous', whereas it is possible they would say that a man is 'handsome' or 'good looking'.

Yes, it is possible to say, "a gorgeous man." You can see how it's used if you google "a gorgeous man".

It sounds fine to us. Evidently, you're just not going to the places where the gorgeous guys hang out, RTL.

I am not a native speaker, but to me it sounds really strange. I have not heard it much, that for the less.