徹底（てってい、teってi）
- thoroughness

The Japanese word 徹底てってい primarily means "thoroughness," "completeness," "going all the way," or "carrying out something to the end." It implies a deep and comprehensive approach, leaving no stone unturned. It suggests a strong commitment to achieve a specific goal or to understand something fully. This word can be used as a noun or as the stem for a verb meaning to "thoroughly do something" or "to carry out [something] completely". 徹底てってい indicates that the action or understanding is not superficial, but rather, done or considered in every aspect.

⚫︎ 問題点を徹底的に調査する。 Translation: To thoroughly investigate the problems. ⚫︎ 安全対策を徹底する。 Translation: To thoroughly implement safety measures. ⚫︎ 彼の意見に徹底的に反対した。 Translation: I completely opposed his opinion.

You can use 徹底てってい in various contexts. ⚫︎When emphasizing the need to be thorough in an action, such as studying, working, or investigating. ⚫︎When expressing a commitment to following a rule or principle completely. ⚫︎When describing a strong feeling or opposition to something. You would use it in formal and informal situations, but its application often lends a slightly more formal tone to a conversation.

⚫︎ The word 徹底てってい is written with the kanji 徹底 and is typically read as てってい in hiragana. ⚫︎ There is no alternate way to write the same meaning but the word can be combined with other verbs to create a verb phrase; for example, 徹底的に (completely, thoroughly). ⚫︎ The okurigana (送りがな) can vary slightly depending on how the word is used. For example, 徹底てっていする (to do thoroughly) will have the verb ending する attached.

⚫︎ 完全 (かんぜん) - "complete," "perfect" ⚫︎ 十分 (じゅうぶん) - "sufficient," "enough" ⚫︎ 徹底的 (てっていてき) - "thorough," "exhaustive" (adjectival form of 徹底) ⚫︎ 詳細 (しょうさい) - "detailed"

⚫︎ 不徹底 (ふてってい) - "incomplete," "inadequate" ⚫︎ いい加減 (いいかげん) - "half-hearted," "irresponsible" ⚫︎ 大雑把 (おおざっぱ) - "rough," "sketchy"

彼は徹底的な分析によって、その問題を解決した。 ・Translation: He solved the problem through thorough analysis. ・Explanation: This sentence illustrates how 徹底てってい can be used to describe a deep and comprehensive method of problem-solving.

会社はコスト削減を徹底するために、新しいシステムを導入した。 ・Translation: The company introduced a new system to thoroughly reduce costs. ・Explanation: This sentence demonstrates 徹底てってい being used to describe a commitment of thorough cost reduction.

The kanji 徹 (tetsu) means "penetrate," "thorough," or "to go through," and 底 (tei) means "bottom," "foundation," or "end." Together, the word implies going to the bottom, covering everything, or being completely thorough.