The oldest word is used to describe a cross between a male horse and a female donkey.
They look like this:
(photo by Just Chaos at https://www.flickr.com/photos/7326810@N08)
but, quite honestly, the chance of bumping into one of them is for most of us rather remote.
Luckily there are other hinnies around.
One of them probably also require the presence of a horse, because a hinny is the sound more usually called a whinny. I say probably because there are people (and I expect you know one) who make that sort of noise when they laugh or express shocked disapproval (and, let's face it, who isn't full of shocked disapproval, nowadays?).
The last hinny is easy because it's used, usually in the North East of England, to address any lovable child or young woman.
For double points, why not see if you can spot one on a horse?
Spot the Frippet: hinny. The horse-donkey word goes right back to the Greek word hinnos. The lovable child word is a variant of honey, which word goes back to the Greek knēkos, which means a yellowish colour, and before that to the Sanskrit kánaka-, which means gold. Hinny meaning whinny appeared in the 1500s and is an imitation of the sound one makes.
So, strictly speaking, you can chalk up a Spot just by saying the word.