厄|やくyaku[2]odaka (tail-high)

1. nounmisfortune; bad luck; evil; disaster
2. noununlucky year; critical year; year (esp. age 25 and 42 for men, 19 and 33 for women) that is considered unlucky

• Synonym災いわざわいNeutralA broad word for calamity or trouble, as in 「口は災いの元」. Covers misfortune in general; unlike 「厄」, it never refers to unlucky years.
• Synonym不幸ふこうNeutralEveryday word for unhappiness or bad luck; it can also refer specifically to the death of a family member.
• Synonym不運ふうんNeutralRefers to bad luck itself, stressing one's fortune rather than any specific disaster; no concrete mishap is required.
• Synonym凶きょうNeutralRefers to bad luck or ill omen; mostly seen as a fortune-slip result, as in 「大凶」.
• Synonym災難さいなんNeutralEveryday word for an unexpected stroke of bad luck, as in 「とんだ災難だ」; the default choice for mishaps.
• Synonym禍まがNeutralThe same word as the entry above; 「禍」 and 「殃」 are only alternative writings. A general term for calamity or trouble.
• Synonym災厄さいやくWrittenWritten word for a calamity that befalls someone, stressing the misfortune of the person who suffers it.
• Synonym厄災やくさいWrittenWritten word for an unexpected calamity; close in meaning to 「災厄」.
• Synonym禍事まがごとWrittenArchaic word for something ominous, or for ill-omened words; essentially unused in modern Japanese.
• Synonym凶事きょうじWrittenWritten word for an inauspicious event such as a funeral; the opposite of 「吉事」.
• Synonym否運ひうんWrittenWritten equivalent of 「不運」, meaning ill fortune with no larger scale implied; very rare — 「不運」 is the usual choice.
• Related難なんNeutralCovers disaster but also shortcomings; often used as a suffix, as in 「水難」 or 「住宅難」.
• Related惨禍さんかWrittenWritten word for a ghastly calamity, often war; on a far larger scale than 「厄」.
• Related災害さいがいNeutralObjective term for natural disasters such as earthquakes, floods and epidemics.
• Related惨事さんじNeutralA tragic or horrific incident, common in news reports; stresses the gruesome scene rather than luck.
• Related凶変きょうへんWrittenWritten term for an ominous turn of events, including an assassination; very rarely used.
• RelatedカタストロフィーWrittenLoanword for a catastrophe or tragic ending; implies a very large scale.
• Related危難きなんWrittenWritten word for life-threatening danger, as in 「危難を逃れる」.
• Related災禍さいかWrittenWritten word for disaster, close to 「災害」; mostly seen in formal prose.
• Related変災へんさいWrittenOld-fashioned written word for an unexpected mishap or disaster, no graver than 「災難」; very rare — say 「災難」 instead.
• Related大難だいなんWrittenA great disaster befalling a person, as in the set phrase 「大難を逃れる」.
• Related大災たいさいWrittenWritten word for a colossal disaster; very rare — 「大災害」 is the normal term.
• Antonym福ふくNeutralGood fortune or blessing; the opposite of 「厄」, as in 「厄を払って福を呼ぶ」.
• Antonym幸運こううんNeutralGood luck or being lucky, as in 「幸運を祈る」; the opposite of 「厄」.

「厄」 itself is mostly folk-belief usage in set phrases like 「厄年」, 「厄払い」 and 「厄除け」. For everyday bad luck, pick 「災難」 (an unexpected mishap) or 「不運」 (poor luck in general); for natural disasters use 「災害」. 「災い」 is a broad word for calamity, and 「不幸」 covers unhappiness or a death in the family. Most of the others are written or rare; a few, such as 「惨禍」 and 「カタストロフィー」, imply a large-scale catastrophe, while rare words like 「否運」 and 「変災」 simply have everyday equivalents.

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

1. （ヤク）特定とくていの年齢ねんれいでふりかかるとされる災厄さいやく。