Hoydon = A romping girl.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
I only remember coming across the word “Hoydon” once, and that was in an early scene in Tess of the d’Urbervilles (Thomas Hardy):
They leant over the gate by the highway, and inquired as to the meaning of the dance and the white-frocked maids. The two elder of the brothers were plainly not intending to linger more than a moment, but the spectacle of a bevy of girls dancing without male partners seemed to amuse the third, and make him in no hurry to move on. He unstrapped his knapsack, put it, with his stick, on the hedge-bank, and opened the gate.
“What are you going to do, Angel?” asked the eldest.
“I am inclined to go and have a fling with them. Why not all of us – just for a minute or two – it will not detain us long?”
“No – no; nonsense!” said the first. “Dancing in public with a troop of country hoydens – suppose we should be seen!”