細心|さいしんsaishin[0]heiban (flat)

1. na-adjective, no-adjectivemeticulous; careful; discreet; scrupulous; prudent
   ほんの些細ささいなことにも細心さいしんの注意ちゅういを払はらわなければならない。↗

   You must give close attention to the merest details.

• Synonym丹念たんねんNeutralPainstaking, attentive care in doing something, as in 「丹念に調べる」. It stresses patience, while 「細心」 stresses being careful and cautious.
• Synonym入念にゅうねんNeutralDoing something with deliberate care, as in 「入念に準備する」. It stresses taking pains over the task, while 「細心」 stresses thoroughness of attention.
• Synonym綿密めんみつNeutralThorough with nothing overlooked, said of plans, investigations and the like, as in 「綿密な計画」. It usually describes the plan itself.
• Synonym緻密ちみつNeutralFine-grained and rigorous; also said of dense texture. Used mostly of plans and thinking, while 「細心」 describes a person's attentiveness.
• Synonym周到しゅうとうWrittenPreparation and consideration so thorough that nothing is missed, as in 「用意周到」. It stresses being fully prepared. Written/formal in tone.
• Synonym念入りねんいりNeutralTaking extra care and trouble over something, as in 「念入りに掃除する」. Frequent in colloquial speech.
• Synonym注意深いちゅういぶかいNeutralAn adjective for staying alert and watchful, as in 「注意深く観察する」. Very close to 「細心」, which usually appears as 「細心の注意」.
• Synonym細かこまかWrittenSmall or fine in detail; can also mean stingy. Mostly as 「細かに」, with a written/formal flavor. 「細心」 describes a person being careful and attentive.
• Synonym細かいこまかいNeutralSmall or minute; can also suggest fussing over trifles or being stingy. 「細心」 is positive, praising careful attentiveness.
• Related細密さいみつWrittenExtremely fine and detailed; used mainly of pictures and depictions, as in 「細密画」. It does not describe a person's carefulness. Written/formal in tone.
• Related精緻せいちWrittenExquisitely fine and precise, said mainly of theories and craftsmanship, as in 「精緻な論理」. Strongly written/formal in tone.
• Related詳しいくわしいNeutralMeans detailed, or knowing a subject well. It is about detailed content or rich knowledge, not about being careful.
• Related詳細しょうさいNeutralDetails or detailed content, as in 「詳細は後ほど」. It describes the content, not a person's attitude.
• Related慎重しんちょうNeutralCautious and steady, avoiding rash action, as in 「慎重に判断する」. It stresses steadiness, while 「細心」 stresses attention to small details.
• Related丁寧ていねいNeutralCareful and thorough, but also polite and courteous. 「細心」 covers only close attention, with no sense of politeness.
• Related正確せいかくNeutralAccurate and free of error, of results or of actions, as in 「正確に入力する」. 「細心」 describes attentive, careful watchfulness.
• Related事細かことこまかNeutralIn exhaustive, every-last-detail fashion, as in 「事細かに説明する」. It describes how detailed the content is.
• Related細々しいこまごましいWrittenMinute and fiddly, often with a nuance of being fussy and cumbersome. Not carefulness in the positive sense. Written/formal in tone.
• Antonym不注意ふちゅういNeutralThe antonym: carelessness or inattention, failing to keep one's mind on things. Directly opposed to 「細心」.
• Antonym軽率けいそつNeutralThe antonym: acting rashly without thinking, as in 「軽率な行動」. Opposed to the cautious 「細心」.
• Antonym大雑把おおざっぱNeutralThe antonym: rough and broad, not bothering with small details. Opposed to 「細心」 with its attention to detail.

Use 「細心」 when every small detail gets attention — most often as 「細心の注意を払う」. For doing a task with care, choose 「念入り」 or 「丁寧」; for steady caution, 「慎重」. For thorough plans or investigations, 「綿密」 or 「緻密」; for complete preparation, 「周到」. 「詳しい」「詳細」「事細か」 concern detailed content rather than carefulness, and 「正確」 is about accuracy. The antonyms 「不注意」「軽率」「大雑把」 describe carelessness or rashness.

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

1. 細こまかい点てんにまで注意ちゅういが行き届いきとどく様子ようす。