The story
- Middle English · inherited fromhobye hors“a stock figure in Morris dances, created by means of an exaggeratedly equine costume”
- English todayhobby horse
From Middle English hobye hors (“a stock figure in Morris dances, created by means of an exaggeratedly equine costume”), equivalent to hobby (“small horse or pony”) + horse.
Etymology from Wiktionary, CC BY-SA 4.0.