徹底的|てっていてきtetteiteki[0]heiban (flat)

1. na-adjectivethorough; exhaustive; complete
   あの男おとこは徹底的てっていてきなエゴイストだ。↗

   That man is an egotist through and through.

• Synonym完全かんぜんNeutralMeans complete or whole, as in 「完全に忘れた」; a broad, everyday word, not tied to how thoroughly an action is carried out.
• Related完璧かんぺきNeutralRefers to being perfect and flawless, focusing on a result with no defects; 「徹底的」 describes the thoroughness of how something is done, leaving nothing out.
• RelatedパーフェクトNeutralLoanword for perfect, common in speech, as in 「パーフェクトな出来」; about a flawless result rather than a thorough method.
• Related丁寧ていねいNeutralMeans careful and conscientious, as in 「丁寧に説明する」; it also means polite, a sense 「徹底的」 does not have.
• Related丹念たんねんNeutralMeans painstaking and meticulous, as in 「丹念に調べる」; stresses scrupulous, patient care in the work itself.
• Related綿密めんみつNeutralMeans minute and scrupulous, as in 「綿密な計画」; typically describes detailed, carefully worked-out plans.
• Related周到しゅうとうNeutralMeans thorough with no oversights, as in 「用意周到」; focuses on preparation being complete.
• Related念入りねんいりNeutralMeans careful and elaborate, as in 「念入りに掃除する」; stresses the time and effort put into the task.
• RelatedすっかりNeutralAdverb meaning completely, as in 「すっかり忘れた」; common in everyday speech, about a state being total rather than how work is done.
• Related十分じゅうぶんNeutralMeans sufficient or enough, as in 「十分に注意する」; stresses there being a sufficient amount, not exhaustive coverage.
• Related入念にゅうねんWrittenWritten/formal word meaning careful and elaborate, synonymous with 「念入り」, as in 「入念な準備」.
• RelatedコンプリートNeutralLoanword meaning complete or having collected everything, as in 「コンプリートする」; mostly used for collections, not for thorough methods.
• RelatedまんべんなくNeutralAdverb meaning evenly and all over, as in 「まんべんなく塗る」; stresses even coverage with nothing missed, not thoroughness of effort.
• RelatedつぶさにWrittenWritten/formal adverb meaning in detail, as in 「つぶさに観察する」; about observing or describing something in full detail.
• Relatedきめ細かきめこまかNeutralMeans fine and attentive, as in 「きめ細かな対応」; stresses careful attention to detail rather than exhaustive effort.
• Related余すところなくあますところなくNeutralSet phrase meaning with nothing held back, as in 「余すところなく伝える」; adverbial, about conveying or showing everything.
• Related洗いざらいあらいざらいNeutralAdverb meaning everything out in the open, as in 「洗いざらい話す」; stresses telling or revealing all, not the manner of doing.
• Related精到せいとうWrittenWritten/formal word meaning meticulous and thorough; rare in daily use — say 「綿密」 or 「周到」 instead.
• Antonym中途半端ちゅうとはんぱNeutralAntonym: half-done or half-hearted, quitting midway — the opposite of doing something thoroughly as 「徹底的」 describes.
• Antonym表面的ひょうめんてきNeutralAntonym: superficial, staying on the surface — the opposite of the deep, thorough approach 「徹底的」 describes.

Use 「徹底的」 for doing something thoroughly and leaving nothing out, as in 「徹底的に調べる」. When the result is perfect, say 「完璧」; for careful, painstaking work, 「念入り」 and 「丹念」 fit better. 「完全」 and 「すっかり」 cover completeness of a state, 「綿密」 and 「周到」 careful planning and preparation, while 「中途半端」 and 「表面的」 are the opposites.

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

1. 漏もれのないように注意ちゅういし、できる限かぎりの手てを尽つくして行おこなわれる様子ようす。