Translation

The Japanese word for "Donkey" is roba ロバ.

Romaji ro ba
Hiragana
Katakana
Kanji
Meaning Donkey Horse
School Level 小2

Loan-word

The word "Donkey" katakanized would be donkī ドンキー.
Romaji do n kii
Katakana
Hiragana

Synonyms

Ass.

Further Reading

Wikipedia: Donkey (ロバ)
ashika 海驢.