かいぜん・改善kaizen[0]heiban (flat)

1. noun, suru verb, transitive verb, intransitive verbbetterment; improvement
   ２国こく間かんの貿易ぼうえき上じょうのアンバランスを改善かいぜんしなければならない。↗

   The trade imbalance between two nations should be improved.
2. nounkaizen (Japanese business philosophy of continuous improvement)oft. written カイゼン

• Synonym改良かいりょうNeutralImproves products, breeds, techniques or methods (「品種改良」), stressing better performance; 「改善」 targets flaws in a situation.
• Synonym改めるあらためるNeutralNative verb for changing or revising things, also mending one's attitude (「態度を改める」); the result is not necessarily good, so its range is wider than 「改善」.
• Synonym正すただすNeutralCorrects errors or straightens posture (「姿勢を正す」), focused on setting things right.
• Synonym向上こうじょうNeutralLevels or quality rising (「品質向上」), stressing upward movement; 「改善」 stresses removing what is bad.
• Synonym進歩しんぽNeutralTechnology, ability or society advancing (「科学の進歩」), overall forward movement; 「改善」 is improvement aimed at specific problems.
• Related改正かいせいWrittenWritten word for revising laws, rules or timetables (「法改正」「ダイヤ改正」); it acts on regulations, while 「改善」 works on actual conditions.
• Related刷新さっしんWrittenWritten word for sweeping out the old for a fresh start (「人事を刷新する」); a stronger, more drastic move than 「改善」.
• Related改革かいかくWrittenReforms systems and organizations (「行政改革」), eyeing the structure itself; 「改善」 can be a small, partial improvement.
• Related修正しゅうせいNeutralCorrects errors or adjusts deviations (「計画を修正する」), centred on fixing what is wrong; 「改善」 centres on making things better.
• Related是正ぜせいFormalFormal term for correcting unfairness or disparities (「格差是正」), seen mainly in official documents and news reports.
• Related革新かくしんWrittenBreaks with old practice to bring in the new (「技術革新」), stressing innovation; 「改善」 improves on the existing basis.
• Related変革へんかくWrittenChanges systems or society from the roots up (「社会変革」), more thoroughgoing than 「改革」.
• Related改修かいしゅうWrittenRepairs or rebuilds structures such as buildings, roads and rivers (「道路の改修工事」); 「改善」 applies to a much wider range of objects.
• Related訂正ていせいNeutralCorrects mistakes (「誤字を訂正する」), usually in text or statements; it does not imply anything gets better.
• Related一新いっしんWrittenRenews everything (「面目を一新する」), stressing a total makeover; 「改善」 only fixes the bad parts.
• Related直すなおすNeutralEveryday verb for repairing or correcting (「癖を直す」), common in speech; 「改善」 leans formal.
• Related持ち直すもちなおすNeutralRecovering from a bad state, as with illness or the economy (「景気が持ち直す」); it improves by itself, while 「改善」 can be deliberate.
• Related立ち直るたちなおるNeutralGetting back on one's feet after a setback (「ショックから立ち直る」), said mostly of people or the market.
• Related進展しんてんNeutralMatters moving ahead and making progress (「交渉が進展する」), with no necessary link to good or bad.
• Related前進ぜんしんNeutralMoving forward or closer to a goal (「一歩前進」), progress in a figurative sense; 「改善」 means removing shortcomings.
• Related矯正きょうせいNeutralCorrecting defects or physical misalignment (「歯列矯正」), applied mostly to the body or habits.
• Related上達じょうたつNeutralSkills becoming more polished (「日本語が上達する」), overall gains in ability; 「改善」 fixes specific flaws, as in 「発音を改善する」.
• Antonym悪化あっかNeutralA situation turning worse (「病状が悪化する」), the direct opposite of the betterment 「改善」 brings.
• Antonym改悪かいあくWrittenChanging something for the worse, often to criticize institutional revisions (「制度の改悪」); the opposite of 「改善」.

Use 「改善」 for fixing shortcomings so a situation gets better. For products or methods pick 「改良」, for laws and rules 「改正」, for systems and organizations 「改革」, for errors 「修正」. In daily speech 「直す」 and 「正す」 are the natural verbs; 「悪化」 and 「改悪」 are the opposites.

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

1. 悪わるい所ところを直なおし、良よくすること。
2. （TQC活動かつどうまたはTQM活動かつどうにおいて）生産性せいさんせいまたは品質ひんしつを向上こうじょうさせること、もしくは納期のうきを短縮たんしゅくさせること。特とくに、品質ひんしつの向上こうじょう、即すなわち歩留ぶどまり率りつを向上こうじょうさせることを言ゆう。