Knob of Butter Share definition Flag A British term denoting some butter, or a more gentlemanly insult when striving to avoid strong language. Richard, you knob of butter. You've spilt my pint of ale all over the table. Knob of Butter by Sensei_Tohru January 9, 2010 0 0 Get merch Get the Knob of Butter mug. Buy Now — $32.95 See more merch