怪奇|かいきkaiki[1]atamadaka (head-high)

1. na-adjective, nounbizarre; strange; weird; mysterious
2. na-adjective, noungrotesque

• Synonym風変わりふうがわりNeutralSuggests someone or something is a bit different from the norm — often a person's character or a thing's style — without the eerie, inexplicable weight of 「怪奇」.
• Synonym奇怪きかいWrittenBizarre and beyond ordinary explanation, as in 「奇怪な事件」. Very close in sense to 「怪奇」, but leans toward written prose.
• Synonym不思議ふしぎNeutralA very common word for the inexplicable, often with wonder or admiration; 「怪奇」 puts more weight on the eerie and grotesque.
• SynonymおかしいNeutralMeans funny or comical, and also that something is off or not right, as in 「様子がおかしい」. Common in speech, with no grotesque or eerie sense.
• Synonym変へんNeutralThe everyday default for strange or off, as in 「変な音」, with a light tone. 「怪奇」 is for things that are bizarre and eerie.
• Synonym妙みょうNeutralA vague, hard-to-pin-down strangeness, as in 「妙な音」; it also means skillful or excellent, a sense 「怪奇」 lacks.
• Synonym不気味ぶきみNeutralUnsettling and creepy, often because you can't tell what lies behind it, as in 「不気味な笑み」. It stresses fear; 「怪奇」 stresses eerie strangeness.
• Synonym珍妙ちんみょうWrittenWritten word for oddness with a comical edge, as in 「珍妙な格好」. Its humorous feel is absent from 「怪奇」.
• Synonym変わったかわったNeutralA plain, matter-of-fact word for unusual, as in 「変わった人」 or 「変わった生き物」. 「怪奇」 stresses eerie strangeness more, and can describe looks too.
• Synonym奇妙きみょうNeutralA common word for the peculiar and inexplicable, as in 「奇妙な体験」. Compared with it, 「怪奇」 puts more weight on eerie strangeness.
• Synonym異様いようNeutralFor a look or atmosphere unlike the norm, as in 「異様な雰囲気」, with a sense of unease. It stresses difference; 「怪奇」 stresses bizarre mystery.
• Synonym奇異きいWrittenWritten word for strangeness that departs from the normal, often 「奇異に感じる」 or 「奇異な目で見る」. It stresses deviation from the usual.
• SynonymミステリアスNeutralLoanword for the mysterious, often with a positive, attractive nuance, as in 「ミステリアスな魅力」. 「怪奇」 leans eerie, with no hint of charm.
• SynonymへんてこCasualColloquial for comically odd things, as in 「へんてこな帽子」. Its funny, laughable feel is something 「怪奇」 never has.
• Synonym奇々怪々ききかいかいWrittenA four-character word for the extremely bizarre, as in 「奇々怪々な出来事」. It pushes the degree of strangeness beyond 「怪奇」.
• Synonym奇態きたいWrittenWritten word for an odd, curious appearance, now rarely used; in daily speech say 「変」 or 「奇妙」. 「怪奇」 stresses eerie strangeness.
• SynonymけったいCasualColloquial Kansai dialect for odd or awkward, as in 「けったいな人」. 「怪奇」 is a written word used mainly of phenomena and stories.
• SynonymへんてこりんCasualColloquial and more playfully teasing than 「変てこ」; describes comical oddness, unlike the eerie strangeness of 「怪奇」.
• Synonym妙ちくりんみょうちくりんCasualColloquial and teasing, for a weird-looking appearance; close to 「妙ちきりん」. Its playful feel differs from the eerie tone of 「怪奇」.
• Synonym怪異かいいWrittenWritten word for strange occurrences, and for ghosts or monsters themselves — a use 「怪奇」 does not cover.
• Synonym妙ちきりんみょうちきりんCasualColloquial and teasing, for an oddness you cannot quite explain; close to 「妙ちくりん」. Its feel differs from the eerie tone of 「怪奇」.
• Related不可解ふかかいWrittenWritten word for what cannot be understood or explained, as in 「不可解な行動」. It stresses intellectual bafflement, not necessarily eeriness.
• Related奇矯ききょうWrittenWritten word for eccentric speech and behavior that departs from the norm; it describes people's conduct, while 「怪奇」 describes events and phenomena.
• Related突飛とっぴNeutralFor ideas or behavior that are startlingly offbeat, as in 「突飛な発想」, sometimes with a tinge of oddness. It stresses surprise; 「怪奇」 stresses eerie mystery.
• Related珍奇ちんきWrittenWritten word for the rare and novel, as in 「珍奇な動物」. It stresses rarity; 「怪奇」 stresses eerie strangeness.
• Antonym平凡へいぼんNeutralOrdinary, with nothing special about it — the direct opposite of the bizarre strangeness of 「怪奇」.
• Antonym普通ふつうNeutralThe most common word for normal or usual; it stands opposite to 「怪奇」 in whether something departs from the norm.

Everyday 'strange' is 「変」 or 「不思議」; eerie, bizarre events or stories take 「怪奇」, as in 「怪奇現象」「怪奇小説」; comical oddness is 「変てこ」. 「奇怪」 is closest in sense but more written; 「奇々怪々」 is stronger; 「不思議」 adds wonder; 「奇妙」「変わった」「妙」 are everyday neutral picks; 「突飛」 stresses the unexpected; 「異様」 stresses difference, with unease; 「不気味」 adds fear; 「ミステリアス」 suggests allure; 「変てこりん」「妙ちくりん」「妙ちきりん」「けったい」 are colloquial and playful; 「奇矯」「奇態」「珍妙」「珍奇」「奇異」「怪異」「不可解」 are written words; antonyms: 「平凡」「普通」.

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

1. 怪あやしく不思議ふしぎなこと。また、そのようなさま。奇怪きっかい。