LogFAQs > #971136048

There is a common misconception about Vergil's name. A lot of people think it's a combination of the words verge and ill. As in a character who is on the verge of being ill. There is even some supporting evidence in that Vergil's DMC3-5 voice actor got the role for having a cold at the time they were making DMC3 and the distinct barfing sound Vergil emits when performing a stinger in DMC3 and 4. While this does make sense and that devil trigger rapid slash spam thing he does in DMC4 would definitely make you dizzy enough to feel ill or at least need to sit down for a while, his name coinciding with it was an unintended coincidence.

Dante and Vergil's names most likely come down to Sparda and Eva's personal preferences or perhaps a funny game where they gave one name they liked and the other a name they disliked, then raised each in accordance with how much they liked their name.
It may have been derived from verdant, suggesting that Vergil was originally destined to be dressed in green, to be the Luigi to Dante's Mario but he defiantly started wearing blue.

Vergil's unyielding bitterness, apparent perception that Dante was the favorite and his fixation on equalling or overcoming Sparda suggest that Vergil has unresolved issues relating to his inability to earn Sparda's approval. I would guess that when Dante and Vergil received their halves of the amulet, Sparda probably made fun of Vergil for being excited about jewellery while simultaneously congratulating Dante for embracing his heritage.
This would find its way into all facets of daily life. Dante would be treated like he was predestined for greatness, destined to defeat Mundus and be playable in Viewtiful Joe, meanwhile Sparda was taking bets on whether Vergil would end up more like a crazed Undertale fan or like Martin Prince from the Simpsons.

Also here's another name. Gilver. I want to make fun of this a lot and say Wanna know how inventive Vergil is when it comes to names? Wanna hear about another one of his OCs? Two birds one stone! but apparently the character Gilver in one of the novels who was originally planned to be a disguised Vergil was changed.
Fortunately we did end up getting a mysterious character who turned out to be Vergil though. The one we got had much more exciting traits than Gilver. Traits like looking as if he teaches magic art at Hogwarts while giving the Slytherins preferential treatment and being pretty much the only player character in the series to cower from a boss and need Nero to handle it for him.