性根|しょうねshoune[0]heiban (flat)

1. nounnature; character; disposition
   こいつの性根しょうねが悪わるいから非ひモテなんだろ。↗

   I expect it's his lousy personality that drives off the ladies.

• Synonym気質きしつNeutralInnate temperament or emotional tendencies, also a psychology term; describes objectively, while 「性根」 stresses one's fundamental heart and often sounds preachy.
• Synonym性分しょうぶんNeutralOne's inborn temperament; used for yourself or others alike, as in 「心配性な性分」 or 「世話好きな性分」.
• Synonym心根こころねNeutralOne's inner heart, often with a warm nuance, as in 「心根の優しい人」; 「性根」 is mostly for lecturing or scolding.
• Synonym気性きしょうNeutralOne's temper, described as rough or mild, as in 「気性が荒い」; focuses on the emotional side.
• Synonym気心きごころNeutralA person's disposition as known to those close to them; typically in 「気心が知れた仲」, someone whose nature you know well.
• Synonym根性こんじょうNeutralGrit and determination, also one's nature; 「根性がある」 praises tenacity, the focus being toughness of spirit.
• Synonym性せいWrittenAn unchangeable nature or fate, with a resigned nuance, as in 「悲しい性」; written/formal.
• Synonym性質せいしつNeutralThe nature of people or things, fairly objective; 「性質が悪い」 judges someone as ill-natured or troublesome, while 「性根」 is for lecturing or scolding.
• Synonym本性ほんしょうNeutralOne's hidden true self, typically in 「本性を現す」 — the moment someone shows their real colors.
• Synonym気立てきだてNeutralRefers to a person's disposition and is mostly used in praise, as in 「気立てがいい」; unlike 「性根」 it carries no lecturing tone.
• Synonym禀性ひんせいWrittenA written/formal word for innate nature, very rare; unlike 「性根」 it has no lecturing tone.
• SynonymきっぷNeutralA person's spirit or bearing; 「気っ風がいい」 praises someone as open and generous, while 「性根」 speaks of one's fundamental character.
• Synonym性情せいじょうWrittenCharacter and feelings; written/formal and little used. In daily speech say 「性格」; reach for 「性根」 when lecturing or scolding someone.
• Synonym心ばえこころばえWrittenOne's heart and disposition, also consideration for others; has an old-fashioned feel and is rare today.
• Synonym気稟きひんWrittenInnate temperament; written/formal and very rare — in everyday use say 「気質」.
• Related性格せいかくNeutralPersonality as a whole; the most common everyday word, neutral and objective, with none of 「性根」's lecturing tone.
• Related質しつNeutralQuality or caliber; read 「たち」 it can judge a person's character, as in 「質の悪い人」; 「性根」 stresses the fundamental heart.
• Related本質ほんしつNeutralThe essence of a thing, or a person's inner character, as in 「彼の本質は優しさだ」; 「性根」 is often used in lecturing.
• Related素質そしつNeutralNatural aptitude or makings, as in 「音楽の素質」; concerns potential rather than character.
• Related天性てんせいNeutralInnate nature or natural talent; stresses what one is born with, as in 「天性の明るさ」.
• Related性さがWrittenAn unchangeable nature or fate, with a resigned nuance, as in 「悲しい性」; written/formal.

For everyday talk about someone's personality, 「性格」 is the default. 「性根」 points to a person's fundamental heart and is mostly used when lecturing or scolding, as in 「性根を叩き直す」 or 「性根が腐っている」. To praise a kind nature, use 「気立て」 or 「心根」. For inborn temperament or temper, 「気質」, 「性分」 and 「気性」 are neutral choices; 「気稟」 and 「性情」 are written/formal and rare.

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

1. 一ひとつのことを長ながくやり続つづける根気こんき。
2. その人ひとの根本的こんぽんてきな心こころの持ち方もちかた。