本性|ほんしょうhonshou[1]atamadaka (head-high)

1. nountrue character; real nature
   わずかの言葉ことばが人ひとの本性ほんしょうを表あらわすことがある。↗

   A few words may betray a man's true character.

• Synonym気質きしつNeutralNeutral. An innate temperament or disposition; 「本性」 stresses the true essence that lies beneath the surface.
• Synonym根性こんじょうNeutralNeutral. Means grit or backbone, which is often praised, and also one's nature, a sense that is often negative, as in 「根性が悪い」; 「本性」 carries no sense of grit.
• Synonym天性てんせいWrittenWritten/formal prose. Innate qualities or talent; 「本性」 typically refers to the true face that comes out.
• Synonym気性きしょうNeutralNeutral. One's inborn temper, how mild or fiery it is; 「本性」 is the true face.
• Synonym気心きごころNeutralNeutral. Often in 「気心が知れる」, knowing each other's temperament; 「本性」 is one's true self.
• Synonym性分しょうぶんNeutralNeutral. An innate disposition, often used when talking about oneself; 「本性」 often means the hidden true face.
• Synonym心根こころねWrittenWritten/formal prose. One's inner depths, often framed as good or evil; close to 「本性」 but more refined.
• Synonym性根しょうねCasualColloquial. One's fundamental character, as in 「性根を入れ替える」; 「本性」 commonly appears in 「本性を現す」.
• Synonym性せいWrittenWritten/formal prose. A person's nature, but also sex and gender; 「本性」 is the innate true character.
• Synonym性質せいしつNeutralNeutral. A person's disposition, but also the properties of things; 「本性」 stresses the true essence hidden underneath.
• Synonym気立てきだてNeutralNeutral. Typically describes a mild, kind disposition and often serves to praise someone; 「本性」 is the innate nature, often the true face revealed.
• Synonym人となりひととなりWrittenWritten/formal prose. A person's character and conduct, mostly a neutral description; 「本性」 stresses the innate nature, the true face.
• Synonym天資てんしWrittenWritten/formal prose. Innate endowments or talent; rare, and 「素質」 or 「天分」 is normally used instead.
• Synonym天質てんしつWrittenWritten/formal prose. Innate talent; rare, and 「才能」 is normally used instead.
• Synonym禀性ひんせいWrittenWritten/formal prose. An innate disposition; rare, and identical in meaning to 「稟性」.
• Synonym賦性ふせいWrittenWritten/formal prose. An innate, endowed disposition; rare, and 「性分」 is normally used instead.
• Synonym資性しせいWrittenWritten/formal prose. Innate disposition and talent; rare, and 「素質」 is normally used instead.
• SynonymきっぷCasualColloquial. An open, generous cast of character, often in 「気っ風がいい」; 「本性」 is the true face.
• Synonym稟性ひんせいWrittenWritten/formal prose. An innate disposition; rare, and 「性分」 or 「性質」 is normally used instead.
• Synonym稟質ひんしつWrittenWritten/formal prose. Innate endowments; rare, and 「素質」 is normally used instead.

Everyday talk about character defaults to 「性格」 and 「性質」. 「本性」 is the innate nature or true face, often in 「本性を現す」. Praise a kind nature with 「気立て」; describe someone's character with 「人となり」. 「気質」, 「気性」, 「気心」 and 「性分」 cover inborn temperament; 「根性」 adds grit, its 'nature' sense often negative; 「心根」 is the inner depths; 「性根」 the fundamental character; 「気っ風」 an open, hearty character. 「天性」 and 「性」 are written; 「天資」, 「天質」, 「禀性」, 「賦性」, 「資性」, 「稟性」 and 「稟質」 are rare literary words — prefer 「素質」, 「才能」 and the like.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 生うまれながらの性質せいしつ。
2. 正気しょうき。