Translation guide
The animal donkey. In Japanese, the most common word is ロバ, a loanword from Spanish/Portuguese. The native Japanese word うさぎうま is rare and literary. There are no common metaphorical extensions like 'stubborn person' that map directly to a single Japanese animal word.
donkey (animal)
Referring to the domesticated donkey, the animal.
The standard modern word for donkey. Used in everyday speech, children's books, and zoology.
There is a donkey on that farm.
A rare, literary native Japanese word for donkey. Literally 'rabbit-horse'. Not used in modern conversation.
In English, calling someone a 'donkey' can imply stubbornness. In Japanese, ロバ does not carry this connotation. To describe a stubborn person, use 頑固な人 (がんこなひと) or 強情な人 (ごうじょうなひと).
Donkeys are smaller than horses.
The word 'usagiuma' appears in old documents.