When you’ve enjoyed some lovely toast whilst totes nakey in your sumptuous bed and your big bottom sinks into your comfy mattress please don’t be alarmed when you stand up to find a multitude of crumbs stuck to your derrière. These are only bum crumbs henceforth known as Brumbs.
Baby please brush off my brumbs… I ate a packet of Jammie dodgers in your bed. Soz.
Brumb is a word that is used when someone is an idiot and also is a smooth brain. Use this word if you want to tell someone they are an idiot without realization.