鼠（ねずみ、nezumi）
- mouse/rat

The word 鼠, pronounced ねずみ (nezumi), primarily means "rat" or "mouse" in English. It refers to small rodents belonging to the family Muridae. The specific meaning can vary depending on context, sometimes encompassing both rats and mice, and other times referring more specifically to one or the other.

⚫︎台所（だいどころ）に鼠が出（で）た！ Translation: A rat/mouse appeared in the kitchen! ⚫︎あの鼠はチーズが好（す）きだ。 Translation: That rat/mouse likes cheese.

This word is used in everyday conversation, literature, and various forms of media to describe rats or mice. It can be used in both formal and informal contexts. When speaking about a specific type, you might use additional words to clarify, such as ドブネズミ (dobu nezumi, sewer rat) or ハツカネズミ (hatsuka nezumi, house mouse).

⚫︎The word is most commonly written using the kanji 鼠. ⚫︎The reading is ねずみ in hiragana. ⚫︎There isn't a katakana version typically used. ⚫︎The okurigana (送りがな) doesn't typically vary.

⚫︎ネズミ (nezumi) - This is simply the word written in katakana, often used for emphasis or to indicate a more foreign or technical feel. It is not exactly a synonym but a different writing style for the same word.

There aren't direct antonyms for 鼠 as it is a noun. Instead, consider the opposite concept, such as words related to cleanliness or aversion, like “cleanliness” or “anti-pest products”.

その鼠は罠（わな）にかかった。 ・Translation: That rat/mouse got caught in the trap. ・Explanation: This sentence uses 鼠 to refer to the animal, highlighting the context of a trap.

鼠年（とし）は幸運（こううん）の年だと言（い）われている。 ・Translation: It is said that the year of the rat is a year of good fortune. ・Explanation: This sentence refers to the Chinese zodiac sign of the rat, implying good luck.

The etymology of 鼠 is not entirely clear. However, it is believed to be an ancient Japanese word. Its origin is thought to be related to the sound the animal makes or the characteristics of the animal.