Brexit means Brexit
Something you say if you are pursuing a hopelessly vague, potentially catastrophic exercise in national self-harm driven by misconceived ideology or the bone-headed illusion that one somehow still rules the waves — you know, the way King Cnut did — and you have just found out that you won’t be able to rely on one’s ancient residual prerogative powers, and you want to brush off uncomfortable questions about what on Earth you think you’re playing at.