Was this question closed because it was about realism/verisimiltude? Or some other reason(s)?
Is it possible to wield a 'greatsword'?
Not that it's a great question, or isn't easily answerable by searching the web for the many articles and videos that discuss the general subject.
It's marked closed as "off-topic".
A comment from one of the people voting to close said in part, "It's about being "realistic" where a lot of systems just do not care about realism."
Are realism questions really off-topic here? It doesn't seem like it.
It's actually a pretty common question, it seems to me, on other RPG sites, especially those for games that ARE somewhat interested in realism/verisimilitude. TFT, GURPS, Harnmaster, Ars Magica, Mythras, Runequest, Aftermath, Traveller, yes, even some D&D players, have at least some interest in what a greatsword is supposed to be, how big and heavy and practical it would be, what a realistic one would look like and how it'd be used, and not only whether various fantasy images could be practical weapons, but which historical swords were practical versus parade swords, which were developed in which period and why, etc etc.