"be on fire" in German to be on fire in Flammen stehen brennen Detailed translations for "be on fire" to be on fire 1. general to be on fire(also: to be a blaze) in Flammen stehen 2. medicine to be on fire brennen{intransitive verb} You could be on fire and I wouldn't know. Source: opensubtitles.org Corpus by OPUS Request review Du könntest brennen und ich würde es nicht merken.