Thing Not To Be Today: gruelling.

 If you go on and on and on then people may begin to find being with you quite gruelling.

Still, they'll probably let you know.

The really interesting thing, of course, is what has being gruelling got to do with gruel?

Is the severely taxing or patience-testing experience that's described as gruelling like trudging through porridge, or gruel?

Well, yes, it is. But sadly that seems to be a coincidence.

illustration by George Cruikshank

Thing Not To Be Today: gruelling. This word popped up in the 1800s and comes from the now-forgotten word gruel, which meant to exhaust or punish. 

Gruel meaning thin porridge has been an English word since the 1300s. It came from Old French, and before than it was a Germanic word. Pleasingly, it has a relation in the word grout, which comes from the Old English word grot, meaning fragment.