希代・稀代|きたいkitai[1]atamadaka (head-high)

1. no-adjective, na-adjectiveuncommon; rare; extraordinary; matchless

• Synonym珍しいめずらしいNeutralThe everyday, most common word for 'rare' or 'unusual', stressing that something is uncommon or novel. Plain, matter-of-fact tone.
• Synonym希有けうWrittenWritten/formal word for 'rare', stressing how seldom something occurs, as in 「希有な例」. Close to 「希代」 but without its tinge of strangeness.
• SynonymめったにないCasualColloquial phrase for things that hardly ever happen, stressing how rarely they occur. Much lighter in tone than 「希代」.
• Related非凡ひぼんWrittenWritten/formal word for 'extraordinary', stressing ability far beyond ordinary people, with a positive slant. No sense of strangeness.
• Related特別とくべつNeutralEveryday word for 'special', stressing difference from the general run. The plainest in tone of these words; no suggestion of rarity.
• Related異例いれいWrittenWritten/formal word for cases that break with convention or precedent, as in 「異例の抜擢」「異例の暑さ」. Lacks 「希代」's sense of being rare in the world.
• Related格別かくべつWrittenWritten/formal word for 'especially' or 'exceptionally good', as in 「格別の味」, with a favorable slant. About being special, not rare.
• Related風変わりふうがわりNeutralNeutral word for 'quirky' or 'eccentric', stressing looks or character that differ from the norm. Has a strange feel but does not stress rarity.
• Related特異とくいWrittenWritten/formal word for 'singular' or 'peculiar', stressing an unusual nature, as in 「特異体質」. Objective in tone.
• Related例外的れいがいてきWrittenWritten/formal word for 'exceptional', stressing that something falls outside the rule. Works at the level of rules and norms, not rarity.
• Related破格はかくWrittenWritten/formal word for breaking with convention — treatment, prices, scale all fit, as in 「破格の値段」. 「希代」 stresses rarity in the world instead.
• Related異色いしょくWrittenWritten/formal word for 'distinctive', stressing a character that sets one apart, as in 「異色の経歴」. About distinctiveness, not rarity.
• Related桁外れけたはずれCasualColloquial word for something wildly off the scale, stressing size or degree far beyond the norm, as in 「桁外れの金持ち」.
• Related人並みはずれたひとなみはずれたWrittenWritten/formal term for abilities or traits that surpass the ordinary person's; limited to human characteristics, unlike 「希代」.
• Related桁違いけたちがいCasualColloquial word for being in a different league, stressing a vast gap in level, as in 「桁違いの強さ」. About degree of difference, not rarity.
• Antonym平凡へいぼんNeutralAntonym: 'ordinary' or 'commonplace', with nothing rare or striking about it. The direct opposite of 「希代」's sense of being rare in the world.
• Antonym凡庸ぼんようWrittenAntonym: written/formal word for 'mediocre', with nothing outstanding at all. The formal opposite of 「希代」's rare-in-the-world sense.

Use 「希代」 (also 「稀代」) for things rarely seen in the world; written/formal in tone, it often appears as 「希代の英雄」 or 「希代の悪党」. For everyday 'rare' or 'unusual', 「珍しい」 is the default, and 「滅多に無い」 covers things that seldom happen; for sheer rarity in formal prose, pick 「希有」. For extraordinary ability use 「非凡」 or 「人並みはずれた」; for off-the-scale degree 「桁外れ」 or 「桁違い」; for cases that break convention 「異例」 or 「例外的」; for distinctive character 「風変わり」 or 「異色」. The antonyms are 「平凡」 and 「凡庸」.

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

1. 世よにも希まれなこと。
2. 不思議ふしぎなこと。