真摯|しんしshinshi[1]atamadaka (head-high)

1. na-adjective, nounsincere; earnest; serious

• Synonym真面目まじめNeutralThe everyday word for serious and honest; describes character and conduct. 「真摯」 is written-style and stresses being sincere and earnest toward people and things.
• Synonym本気ほんきNeutralColloquial; means being in earnest rather than joking, as in 「本気で取り組む」. 「真摯」 is formal and stresses sincerity.
• Synonym真剣しんけんNeutralStresses a serious attitude that is not careless, as in 「真剣に考える」; 「真摯」 adds a formal, sincere tone.
• SynonymシリアスNeutralLoanword for grave and solemn; mostly describes the mood of a story or plot, but 「シリアスな態度」 is also possible. 「真摯」 stresses sincerity.
• Related一途いちずNeutralSingle-minded; stresses devoting yourself to one thing or one person, rather than sincerity toward people and matters in general.
• Related熱心ねっしんNeutralZealous and enthusiastic; stresses the passion you put in and lacks the note of sincerity that 「真摯」 carries.
• Related一生懸命いっしょうけんめいNeutralEveryday word for going all out, trying with all your might; it is about effort, not sincerity.
• Related懸命けんめいWrittenWritten-style; about striving hard, as in 「懸命に働く」; the focus is on effort rather than sincerity.
• Related生真面目きまじめNeutralOverserious; suggests someone rigid and straight-laced, often with a teasing tone. 「真摯」 is a positive word for sincerity.
• Related真正直ましょうじきNeutralRare and slightly tongue-in-cheek; stresses being completely honest and upright. 「真摯」 is a standard formal word for sincerity.
• Related熱誠ねっせいWrittenWritten-style and rare; stresses warm, heartfelt enthusiasm, while 「真摯」 stresses being earnest and serious.
• Related摯実しじつWrittenWritten-style and rare; in modern Japanese 「真摯」 is the usual word for this sincere, serious meaning.
• Antonym軽薄けいはくNeutralAntonym: frivolous and shallow; the opposite of the solemn, sincere stance of 「真摯」.
• Antonym不誠実ふせいじつWrittenAntonym: dishonest and irresponsible; the opposite of the sincere, earnest attitude 「真摯」 describes.

「真摯」 is written-style: sincere and earnest toward people and things, as in 「真摯に受け止める」 or 「真摯な態度」. In daily speech say 「真面目」; for a serious attitude 「真剣」; for being in earnest 「本気」; for giving it your all 「一生懸命」. The opposites are 「不誠実」 and 「軽薄」.

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

1. まじめで懸命けんめいにやるさま。