whonbatto means "Wombat" in English.
It's a katakanization, a loan-word.

whonbatto in katakana is ウォンバット.
whonbatto is not usually written with hiragana.
whonbatto does not have kanji.
Romaji who n ba tto
Katakana ウォ

Orthography Notes

  • ウォ is a compound kana representing a single syllable with multiple characters.
  • ット contains a small tsu ッ which makes the consonant of the syllable longer.
Wikipedia: ウォンバット