Sometimes, when I'm trying to find rhymes, I start typing words that might or might not work, and I let WordPerfect be the arbiter. I was trying to see if it would accept "chinny" as a word - we all know what it means, after all: it's the diminutive of chin, just as skinny is the diminutive of skin. Wait.
Anyway, my finger neglected to depress the "C" and I typed hinny. But it didn't get a red underline, so I looked it up.
Apparently, it's the other thing you can get when you cross a horse with a donkey.
If you really want to know, here is the rule:
Female horse, male donkey, that's a mule.
When a female donkey makes a male horse whinny,
the end result of that tryst is a hinny.
I read on, I'm no fool,
I know you, too, are puerile.
Just one - the entry "mule" -
includes the fateful: sterile.
(Hinny also doesn't seem to have the connotation of being stubborn. Coincidence?)