Playing with language

In Flashman at the Charge by George MacDonald Fraser I come across this passage.  

And it would have fallen out like that, too, but for the infernal ingenuity of that kitten-tickling besom—Kutebar was right: Ko Dali should have whaled the wickedness out of her years ago.

Besom?  What that?

be·som

noun

a broom made of twigs tied around a stick.

The Ko Dali's daughter character (an actual historical figure) is a cypher, an iron rod of will and intelligence attired in coy femininity.  The twigs (coy femininity) around the stick (the iron rod of intelligence and will) makes sense as a metaphor.  But only if you know what a besom is.  

There is something pleasing about the compliment an author pays his reader when he uses a novel metaphor with an obscure word and apparently anticipates the reader will understand.