効果|こうかkouka[1]atamadaka (head-high)

1. no-adjectiveeffect; effectiveness; efficacy; result
   彼かれらがいくら弁解べんかいしても彼女かのじょには何なんの効果こうかもなかった。↗

   Their excuses cut no ice with her.
2. nouneffects (e.g. sound effects, visual effects, special effects)

• Synonym効き目ききめCasualColloquial word for how well something—especially medicine—works, as in 「薬の効き目」. More conversational and concrete than 「効果」.
• Synonym効能こうのうWrittenWritten word for the beneficial effects of a medicine or treatment, as in 「温泉の効能」. Typical of drug and hot-spring descriptions.
• Synonym実効じっこうWrittenWritten word for actual, real-world effect, as in 「実効性のある対策」. Stresses that something truly works.
• Synonym効力こうりょくNeutralPotency or validity, as in 「法的効力」 and 「薬の効力」. Focuses on whether something can take effect.
• Synonym効こうWrittenWritten word for efficacy. Rarely used alone; appears mostly in set phrases like 「効を奏する」.
• SynonymインパクトCasualColloquial loanword for impact or punch, as in 「インパクトがある」. Covers strong impressions rather than efficacy.
• Synonym作用さようNeutralAction or operation, as in 「副作用」. Focuses on how something works on something else—the mechanism.
• Synonym利きききCasualColloquial word for how well something works, as in 「薬の利きがいい」. Often used as a suffix.
• Synonym効験こうけんWrittenWritten word for efficacy with a religious tinge, as in 「神仏の効験」—the miraculous workings of gods or Buddhas.
• Related影響えいきょうNeutralInfluence or impact, as in 「影響が出る」. Focuses on ripple effects on something else, without judging good or bad.
• Related成果せいかNeutralPositive results or achievements, as in 「研究成果」. Highlights what effort has actually produced.
• Related結果けっかNeutralResult or outcome, as in 「試験の結果」. Can be good or bad, so more neutral than 「効果」.
• Related収穫しゅうかくNeutralHarvest, or figuratively a gain, as in 「今回の収穫」. A metaphor for benefits gained from an experience.
• Related結晶けっしょうWrittenWritten word for the crystallization of effort, as in 「努力の結晶」. Stresses something distilled and embodied.
• Related産物さんぶつWrittenWritten word for a product of something, as in 「時代の産物」. Stresses that it was produced by that thing.
• Related実りみのりNeutralFruits or harvest of effort, as in 「実りある議論」. Carries a harvest metaphor; common even in formal settings.
• Related所産しょさんWrittenWritten word for a product or result. Less common than 「産物」 and more literary.
• Related結実けつじつWrittenWritten word for bearing fruit, as in 「努力が結実する」. Describes efforts finally paying off.
• Related賜物たまものWrittenWritten word for a boon or good result, as in 「努力の賜物」. Frames the outcome as something bestowed.
• RelatedエフェクトCasualColloquial loanword for sound or visual effects, as in 「サウンドエフェクト」. The everyday word for film and broadcast effects.
• Antonym無効むこうNeutralAntonym: having no effect or being invalid, as in 「治療が無効だった」. The opposite of 「効果」.

For effects, 「効果」 is the default. For medicine, say 「効き目」 or 「利き」 colloquially and 「効能」 in written descriptions; use 「効力」 for potency or validity, 「実効」 for real-world effect, 「成果」 or 「賜物」 for good results, 「エフェクト」 for film effects, and 「無効」 when something has none.

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

1. 物事ものごとから生しょうじる結果けっか。好このましいものを指さすことが多おおいが、必かならずしもそうでない場合ばあいもある。
2. 映画えいが等とうで、場面ばめんの実感じっかんを出だすこと。
3. 柔道じゅうどうの判定はんていの一ひとつ。