Translation

The Japanese word for "Serpent" is hebi 蛇.

Romaji he bi
Hiraganaへび
Katakanaヘビ
Kanji 蛇
School Level 中

Loan-word

The word "Serpent" katakanized would be sāpento サーペント.
Romaji saa pe n to
Katakanaサーペント
Hiraganaさーぺんと

Synonyms

Scientific name: Serpentes.

Further Reading

Wikipedia: Snake (ヘビ)