不安|ふあんfuan[0]heiban (flat)

1. noun, na-adjectiveanxiety; uneasiness; worry; apprehension; fear; insecurity; suspense
   その知しらせで彼かれの不安ふあんが増ました。↗

   The news added to his anxiety.

• Synonym気がかりきがかりNeutralSomething that stays on your mind and won't let go, with a fairly concrete object: 「子供のことが気がかりだ」. Neutral register.
• Synonym心配しんぱいNeutralThe everyday word for worrying about something concrete; also caring for someone. 「不安」 stresses feeling unsettled rather than a specific worry.
• Synonym懸念けねんWrittenConcern over problems that may arise; mostly in news and official writing: 「懸念を示す」. Formal register.
• Synonym憂慮ゆうりょWrittenDeep concern over a serious situation, mostly about national or social issues. Formal written word.
• Synonym憂いうれいWrittenSorrow or lingering worry, as in 「後顧の憂い」; carries a literary flavor.
• Synonym心労しんろうWrittenMental strain caused by worrying, as in 「心労が重なる」. Written register.
• Synonym気遣いきづかいNeutralMostly thoughtfulness and consideration for others; the worry sense is secondary.
• SynonymおそれNeutralFear itself, or the risk that something may happen: 「雨の恐れ」. Stresses dread or likelihood rather than general unease.
• Synonym不安心ふあんしんWrittenWritten-style word for not feeling at ease, but rare even in writing; 「不安」 is the normal choice.
• Synonym心もとないこころもとないNeutralAn adjective for feeling unsure because someone or something is unreliable: 「一人では心もとない」.
• Synonym物案じものあんじWrittenAn old-fashioned, literary word for worry; rarely used in modern Japanese.
• Synonym心痛しんつうWrittenHeartache or anguish from worry, as in 「ご心痛のほど」; used in formal, courteous expressions.
• Related気遣わしいきづかわしいWrittenA written-style adjective for something that causes worry or unease.
• Related動揺どうようNeutralEmotional agitation or being flustered, often after a shock: 「動揺を隠せない」.
• Related不安げふあんげNeutralDescribes someone looking anxious; used for other people's appearance, not your own feelings.
• Related鬼胎きたいWrittenA literary word for a fear secretly harbored; also a medical term (hydatidiform mole). Not used in daily speech.
• RelatedひやひやCasualColloquial mimetic word for being on edge or sweating over something: 「見ていてひやひやした」.
• Related憂虞ゆうぐWrittenA rare written word for fear and worry; essentially obsolete in modern usage.
• Antonym安心あんしんNeutralRelief or peace of mind; the direct opposite of 「不安」.
• Antonym安定あんていNeutralStability in emotions or life; the opposite of the unsettled state of 「不安」.

For a general sense of unease or insecurity, use 「不安」. For worry about something concrete, use 「心配」; something weighing on your mind is 「気がかり」; concern over possible problems, as in news or official writing, is 「懸念」. 「ひやひや」 is colloquial for being on edge, 「恐れ」 covers fear or risk, and 「動揺」 is agitation after a shock. Many others are written or rare: 「憂慮」, 「憂い」, 「心労」, 「心痛」, 「物案じ」, 「憂虞」, 「鬼胎」. Antonyms: 「安心」 (relief) and 「安定」 (stability).

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

1. 心配しんぱいで落ち着おちつかないこと。