ひどい・酷い・非道いhidoi[2]nakadaka (mid-high)

1. i-adjectivecruel; heartless; hard; harsh; severe
2. i-adjectiveviolent; intense; strong; heavy; extreme
3. i-adjectivevery bad; terrible; awful
   この薬くすりはひどい味あじがする。↗

   This medicine tastes horrible.
4. i-adjectiveexcessive; exorbitant; unreasonable; outrageous; unfair; unjust

• Synonym残酷ざんこくNeutralCruelty that makes people suffer; also describes harsh reality or fate, as in 「残酷な現実」.
• Synonym残忍ざんにんNeutralDoing brutal things without compunction, as in 「残忍な手口」; stresses a ferocious, savage nature.
• Synonym無情むじょうWrittenWritten word for having no compassion, as in 「無情の雨」; can also refer to lifeless, inanimate things.
• Synonym冷酷れいこくNeutralCold, unfeeling attitude, as in 「冷酷な態度」; stresses an icy lack of warmth.
• Synonym残虐ざんぎゃくWrittenWritten word for savage, ferocious brutality, as in 「残虐な行為」; stresses violence.
• Synonym非道ひどうWrittenWritten word for what defies morality and human feeling, as in 「極悪非道」; stresses unreasonableness.
• Synonym暴虐ぼうぎゃくWrittenWritten word for tyrannical cruelty, as in 「暴虐の限り」; typically of those in power.
• Synonym極悪ごくあくWrittenWritten word for extreme, utter wickedness, as in 「極悪人」; stresses how deep the evil runs.
• Synonym無残むざんWrittenWritten word for scenes too dreadful to look at, as in 「見るも無残な姿」; stresses a tragic, miserable outcome.
• Synonym凶悪きょうあくWrittenWritten word for vicious, savage evil, as in 「凶悪犯罪」; typical of crime reporting.
• Synonym凄まじいすさまじいNeutralA staggering, overwhelming degree, as in 「凄まじい音」; can be praise or blame and is not limited to cruelty.
• Synonym無慈悲むじひWrittenWritten word for a complete lack of mercy or pity, as in 「無慈悲な仕打ち」; stresses absence of compassion, where 「酷い」 is more colloquial and broader in range.
• Synonym冷酷無残れいこくむざんWrittenFour-character compound for cold-blooded cruelty taken to the extreme, as in 「冷酷無残な犯行」; the tone is extremely heavy.
• Synonym非人道的ひじんどうてきWrittenWritten word for what violates humanitarian principles, as in 「非人道的な扱い」; frequent in human-rights contexts.
• Synonym冷酷無情れいこくむじょうWrittenFour-character compound for cold-heartedness unmoved by others' suffering; stronger in emphasis than 「冷酷」.
• Synonym酷薄こくはくWrittenWritten word for harsh, cold-hearted people, as in 「酷薄な人」; stresses thinness of feeling.
• Synonym惨酷さんこくNeutralThe same word as above; also written 「惨酷」, with exactly the same meaning.
• Related過酷かこくWrittenWritten word for excessive harshness, as in 「過酷な労働」; stresses conditions beyond what one can endure.
• Related悪質あくしつNeutralMalicious or nasty in nature, as in 「悪質な詐欺」; stresses the wicked quality of the act itself.
• RelatedむごいCasualColloquial; covers scenes too dreadful to watch as well as harsh treatment of people, as in 「むごい仕打ち」; more tragic in flavor than 「酷い」.
• RelatedこっぴどいCasualColloquial, meaning severely or thoroughly, as in 「こっぴどく叱られる」; stresses the severity of the degree.
• RelatedむごたらしいWrittenWritten word for cruelty too horrible to look at, as in 「惨たらしい事件」.
• Antonym優しいやさしいNeutralAntonym of 「酷い」 in its cruel sense: warm, kind and considerate, as in 「優しい人」.
• Antonym穏やかおだやかNeutralAntonym of 「酷い」 in its intense, violent sense: mild and calm, as in 「穏やかな天気」.

For cruel, harsh or terrible things, 「酷い」 is the everyday default. In more formal prose choose 「残酷」 or 「残忍」 for cruelty, 「冷酷」 for cold-heartedness, 「惨い」 or 「無残」 for scenes too horrible to watch, 「過酷」 for conditions harsher than one can bear, and 「凶悪」 for vicious crime. The four-character compounds and other written terms above belong to heavy, formal writing. For the opposite, 「優しい」 means kind and gentle.

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

1. 残酷ざんこくだ、冷血れいけつだ、苛烈かれつだ、薄情はくじょうだ。
2. みじめだ、散散さんざんだ。
3. 非常ひじょうに悪わるい。なっていない。
4. （甚じんい）程度ていどが非常ひじょうに強つよい。はなはだしい。
5. （甚じんい）（「ひどく」の形かたちで副詞ふくし的てきに）非常ひじょうに。はなはだしく。