As a non-native speaker who lives in the US and does a lot of English. Killer also means twoplus good or exciting in some contexts. "Killer app" for instance.

As a non-native speaker who lives in the US and does a lot of English. Killer also means twoplus good or exciting in some contexts. "Killer app" for instance. "Slang. something or someone having a formidable impact, devastating effect, etc.:" Orcas are nothing if not formidable.