愚か|おろかoroka[1]atamadaka (head-high)

1. na-adjectivefoolish; stupid; silly
   そんな愚おろかなことを言ゆうな。↗

   Do not say such foolish things.

• Synonym間抜けまぬけCasualColloquial. Muddle-headed, prone to botching things; often an insult. 「愚か」 is more written in tone, about poor thinking and foolish judgement.
• SynonymばかCasualThe most common way to call someone an idiot, also meaning silly or absurd. 「愚か」 is more written and serious, though it too can carry a critical edge.
• Synonym馬鹿らしいばからしいNeutralNeutral. Absurd and not worth doing; mostly evaluates things or situations. 「愚か」 mostly evaluates people's ideas and actions.
• SynonymアホCasualColloquial, the usual Kansai way to call someone a fool. 「愚か」 is a written expression and is not used as a form of address.
• Synonym愚ぐWrittenA single character, written/formal prose, as in 「愚の骨頂」; also used as a humble first-person pronoun. Everyday speech uses 「愚か」.
• Synonym愚劣ぐれつWrittenWritten/formal prose. Foolish and inferior, worthless and contemptible — a heavy tone. 「愚か」 is comparatively neutral.
• Synonym愚鈍ぐどんWrittenWritten/formal prose. Foolish and slow, slow to react. 「愚か」 focuses on failures of judgement.
• Synonym愚昧ぐまいWrittenWritten/formal prose. Ignorant and unable to grasp reason; more literary than 「愚か」.
• Synonym愚蒙ぐもうWrittenWritten/formal prose and rare. Means ignorant; in everyday speech use 「愚か」.
• Synonym愚かしいおろかしいWrittenAn adjective close in meaning to 「愚か」, slightly more written, often judging behaviour. 「愚か」 is the more common choice.
• SynonymどんくさいCasualColloquial. Slow-moving, clumsy, not quick on the uptake. 「愚か」 is about the mind and judgement.
• Synonym遅鈍ちどんWrittenWritten/formal prose and rare. Slowness of movement or action — a different notion from the foolishness of 「愚か」.
• Synonym痴鈍ちどんWrittenWritten/formal prose and rare. Dull-witted and slow; in daily speech say 「愚か」 or 「鈍い」.
• SynonymとろいCasualColloquial. Slow to react or slow-moving; can also describe a weak fire. 「愚か」 is about mental foolishness.
• Synonym魯鈍ろどんWrittenWritten/formal prose. Naturally dull-witted, slow by nature; everyday speech uses 「愚か」.
• SynonymとろくさいCasualColloquial with a dialect flavour. Slow, sluggish, dull. 「愚か」 points to careless thinking.
• Related浅はかあさはかNeutralNeutral. Shallow, short-sighted thinking, as in 「浅はかな考え」. 「愚か」 covers a broader range.
• RelatedのろまCasualColloquial. An insult for someone slow-moving and slow to react. 「愚か」 leans toward foolish judgement.
• RelatedアホくさいCasualKansai colloquial. So silly it is not worth doing. 「愚か」 is the written-register word for foolishness.
• Related阿呆らしいあほらしいCasualKansai colloquial. Absurd and laughable. 「愚か」 judges the foolishness of people or their actions.
• RelatedおっちょこちょいCasualColloquial. A rash, careless scatterbrain. 「愚か」 is foolishness in judgement.
• Related馬鹿げたばかげたNeutralNeutral prenominal form meaning absurd, as in 「馬鹿げた考え」. 「愚か」 can stand alone as a predicate and modify people.
• RelatedバカくさいCasualColloquial. So silly it feels pointless. 「愚か」 is more written and serious.
• Antonym賢いかしこいNeutralNeutral. Bright, clever, wise — the direct opposite of 「愚か」.
• Antonym利口りこうNeutralNeutral. Sharp and sensible; also describes well-behaved children and pets. The opposite of 「愚か」.

Use 「愚か」 in written or serious prose to say a person or their behaviour is foolish. For calling someone an idiot in speech, 「馬鹿」 and 「アホ」 are the everyday choices. For shallow, short-sighted thinking use 「浅はか」; for being slow or clumsy use 「鈍くさい」 or 「とろい」; for a rash, careless person use 「おっちょこちょい」. The many written compounds (愚劣, 愚鈍, 愚昧, 魯鈍, etc.) are literary and rare in daily talk.

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

1. 物事ものごとの考かんがえが足たりないさま。
2. ばかばかしいこと。ばかげていること。