I was reading myself to sleep with a Wodehouse novel when I came across a reference to "a costermonger calling attention to his
Brussels sprouts." I realized that I have known the word costermonger (fruit and vegetable seller) for years but have never known what a coster is.

Any well-read person will have learned various words of that type - costermonger, ironmonger, warmonger, hatemonger. Clearly, mongers are getting more disreputable as time passes. Come to think of it, what is "mong"?

Just so you won't lie awake worrying about this, I looked it up in my unabridged dictionary. Coster- comes from costard, a kind of apple. "Mong" goes back to the Anglo Saxon (with a nod to some Latin verb) and means to trade or barter. As early at the 17th C it was associated with the slave trade and was beginning to get a bad reputation.

"Mong" shows that not all four-letter Anglo-Saxon words have to be written with stars replacing the vowels.

It might be interesting to follow up on costard and see if we get to Custard and maybe even the Battle of the Little Big Horn, but not tonight.