Word To Use Today: nelly.

 I don't know what happened to nelly. 

To be honest, I was never even sure who (or what) nelly was. When I was a child, and spending even more time than I do nowadays wondering what the heck was going on, the answer to a question like Is it all right to come into the house in my wellies? Might be Not on your nelly, I've just scrubbed the floor!

It meant certainly not, that was clear enough, but otherwise the expression was entirely opaque.

The expression is (or has been) used in Australia, too.

I know now that the expression was originally not on your nelly duff, which is rhyming slang for puff. 

Not on your puff means not on your life (life here being equated with breathing or puffing). PG Wodehouse uses puff in this way in The Code of the Woosters: 'Look at that frightful ass Spode swanking about in footer bags! Did you ever in your puff see such a perfect perisher?'

This, sadly, still doesn't tell us who Nelly Duff was, but nelly has long been established as a term for a fool, and something that's duff is something that's useless or broken; and so there would never have been very much expected of a Nelly Duff, poor girl.

Still, she's famous, now; which is a fact to encourage us all.

Word To Use Today: nelly. This used to be used commonly as a short form of Helen. Rather strangely, given the associations of nelly, the name Helen might come either from the Greek elane, torch or Selene, moon. But in either case it's something bright.