不審|ふしんfushin[0]heiban (flat)

1. noun, na-adjectivedoubt; suspicion; question; strangeness
   警官けいかんが不審ふしんな歩行者ほこうしゃをじっと見みつめていた。↗

   A policeman was gazing at a suspicious pedestrian.

• Synonym疑わしいうたがわしいNeutralWorth doubting, hard to tell if true, as in 「疑わしい証拠」; stresses credibility, while 「不審」 stresses something unclear that arouses suspicion.
• Synonym怪しいあやしいNeutralSuspicious or not quite right; the most common choice in everyday speech, as in 「怪しい人」, and covers a broad range of senses.
• Synonym疑いうたがいNeutralA noun for doubt itself, as in 「疑いをかける」; focuses on the act of doubting, not on a suspicious person or thing.
• Synonym疑惑ぎわくWrittenFormal noun for suspicion of wrongdoing, as in 「疑惑が浮上」; typical of news reports.
• Synonym疑念ぎねんWrittenA noun for doubts held in one's mind, as in 「疑念を抱く」; leans toward written prose.
• Synonym胡散臭いうさんくさいNeutralShady and untrustworthy, of unclear origin, carrying strong distrust, as in 「胡散臭い話」.
• Related怪しげあやしげNeutralLooks suspicious, as in 「怪しげな男」; stresses the outward impression rather than actual doubt.
• Relatedきな臭いきなくさいNeutralSuggests gunpowder in the air — a tense situation, or something fishy going on; stresses the uneasy atmosphere rather than the suspicion itself.
• RelatedいかがわしいNeutralSuspicious or indecent and improper, as in 「いかがわしい店」; carries a moral, disapproving nuance.
• Related訝しいいぶかしいWrittenBaffling, hard to make sense of, as in 「訝しげな顔」; a written-style word.
• RelatedうろんWrittenDescribes a suspicious, fishy air; an old-fashioned word rarely used in modern Japanese.
• Antonym確信かくしんNeutralA noun for firm conviction, believing something without any doubt; the direct opposite of 「不審」.
• Antonym信用しんようNeutralA noun for trust and credit, relying on someone as trustworthy; the opposite of the doubting 「不審」.

Use 「不審」 for people or things that arouse suspicion because of something unclear, as in 「不審者」「不審な点」「不審な死」. For everyday suspicion pick 「怪しい」; if the truth is hard to verify, 「疑わしい」; for untrustworthy, 「胡散臭い」; for suspicion of wrongdoing in the news, 「疑惑」. For conviction, use 「確信」.

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

1. 疑問ぎもんに思おもうこと。また、そのさま。