In reply to:

One word, primary sense different in each country, but both senses understood in both. So UK 'mad' = insane, but also understood as crazy; US conversely.


What is the difference between "insane" and "crazy?" My American Heritage defines "insane" as "afflicted with insanity" and "crazy" as "affected with madness; insane." Other than "insane" being a more formal term, the two terms are used interchangeably in the US.