https://en.wikipedia.org/wiki/List_of_terms_used_for_Germans#Hun_.28pejorative.29
Yeah, in certain cases, calling a Hungarian a Hun is offensive. It's basically calling a person a barbarian-savage-nazi.
Depends if it's use comes from not knowing about it's past derogatory uses, or intentional malice, and if the person addressed knows about it's meaning. Like with every name-calling really.
Btw, you can safely call any young person that, most likely they have no clue what it means, but the older generation and more geeky kids might be pissed of lol Also it's a term I haven't really seen or heard used, I guess it's gone out of fashion since WW2 ended.
Personally, I know you are not trying to attack me by saying that, so I wouldn't be offended. I would laugh and tell you about it's historical meaning and why you might offend someone with that. Just like I did I guess.
Also I don't really care what anyone calls me as long as it doesn't involve my flying, or disputes my beer drinking skills :smile: