one thing i know, it's something like ankou, but that'd be edgy as all hell
Combining two above ideas: How about Corvid Harbinger? Corvids are the family Crows and Raven's come from, and Harbingers are typically forerunners, so with Qrow being Ozpin's scout and spy, would seem fitting eh? If not Corvid, then maybe Corvus, the Crow Constellation?
Nah, too edgy, and the Harbinger part doesn't mash well with Qrow.
Also, Corvus literally means Crow, it's exactly the same as Corvid.
I prefer Bad Omen than Ill. Those were the best names of the ones suggested.
Btw, if Qrow named his weapon, it makes sense he did it before working for Ozpin, (even before meeting him), so anything that relates it to that mission is very unlikely
Guys, cmon. We all know the name of his weapon, it's "Happy Hour"
Actually the greek titan Kronos was the titan of time, mor of Ozpins taste. Kronos ate his own children until they stopped him and threw him into tartaros. I do like the name iii Omen. But if we are going to the greek side of things, underworld might be a good name, cause in greek mythology the underworld is a place of death. And bad luck to those who venture in alive. Another name could be Stynx. Like the river Stynx in the underworld, the one that granted Hercules his 'immortal' body. So i vote on Qrows weapons name to either be Underworld or Stynx.