お尻（おしり、oshiri）
- buttocks

The Japanese word お尻 refers to the buttocks or the rear end. It's a common and generally polite term for this body part. The word is sometimes considered slightly less formal than other anatomical terms, making it suitable for a wider range of conversational contexts.

⚫︎ 赤ちゃんのお尻が可愛い。 Translation: The baby's bottom is cute. ⚫︎ お尻をぶつけた。 Translation: I bumped my bottom. ⚫︎ 犬がお尻を振っている。 Translation: The dog is wagging its tail. (lit. The dog is shaking its bottom.)

⚫︎ お尻 is used in casual and everyday conversation. ⚫︎ It's generally acceptable to use it in most contexts, including talking about children, animals, or one's own body. ⚫︎ However, in very formal situations or when discussing medical matters with a doctor, other more clinical terms might be preferred.

⚫︎ The word is typically written in hiragana as おしり。 ⚫︎ The kanji form is 尻, but it's less common to see the kanji used alone. The kanji 臀 (hip, buttocks) is even less common. ⚫︎ The okurigana (hiragana following the kanji) doesn't have variations.

⚫︎ おしり（hiragana version - same meaning) ⚫︎ おしりの穴 (more direct, slightly vulgar: "anus") ⚫︎ おしりの肉 (flesh of the buttocks) ⚫︎ おしりを叩く (to spank the buttocks) ⚫︎ 臀部(donbu) - Medical term for the buttocks (formal) ⚫︎ ケツ - Colloquial and often vulgar term for "butt" (slang)

⚫︎ While there isn't a direct antonym, body parts at the opposite end of the body could be considered in a metaphorical sense, such as 頭（atama: head）or 顔（kao: face).

子供がお尻を掻いている。 ・Translation: The child is scratching their bottom. ・Explanation: This sentence shows a common situation where お尻 would be used to describe the child's action.

転んで、お尻を打った。 ・Translation: I fell and hit my bottom. ・Explanation: This demonstrates the use of お尻 to describe an injury.

The word お尻 is a compound word. お is an honorific prefix, and 尻 refers to the bottom or the rear. The お is often used to make the word sound less blunt and more polite.