Negation and lack with 不
The kanji 不 functions as a marker of not, non-, and lack. In compounds it usually negates or reverses the meaning of the following element, creating words for absence, impossibility, defect, or insufficiency.
Limits and Inability
不可能 (Impossible)
不可能 means impossible or not feasible.
It combines 不 (not) with 可能 (possible) to show not possible.

Sonoko is invited to a band’s after party. During the get-together, the band’s singer Tatsuya eats a rice ball only to collapse and die. The police are called in, and Inspector Megure discovers the victim was poisoned. He accuses the man who prepared the food, but Conan bites into a rice ball to show it’s safe. The victim’s manager, Mari, agrees.
- 麻理
( : - 「無差別
( 殺人( ならともかく、たまたま達也( が食( べたオニギリだけに、あらかじめ毒( を仕込( むのは不可能( じゃありません?」- “If it were indiscriminate murder, that's one thing but since it was just the rice ball Tatsuya happened to eat, wouldn't it be impossible to poison it beforehand?”
- 目暮
( : - 「た、確
( かにそうだが…」- “Th-that's true.”
Negative States
不安 (Anxiety)
不安
It combines 不 (not) with 安 (peaceful) to show a lack of ease.

During a visit with Anzu’s family, Makoto receives a request to babysit for another witch. Things are fine at first, but after a while, rain begins to pour inside. Anzu’s mother realizes that the child they’re watching over has rain magic.
- 杏子
( の母( : - 「小
( さいうちはコントロールできないんだろうね。不安( になると今( みたいに降( らせちゃうんだね」- “You don't have control while you're small, right? When he's uneasy, it pours like just now.”
- 真琴
( : - 「なるほど。そうですよね。いきなり知
( らない所( じゃ心細( いですよ。我慢( してたんですね」- “I see. So that's it. It's a little scary suddenly being in a place you don't know. You've been patient, haven't you?”
不良 (Defective)
不良
It combines 不 (not) with 良 (good) to show not good.

Kenji thinks Kyouko is upset because he and Hikari don’t get along well.
- ケンジ:
- 「オレは不良
( のフリをしてるだけだってヒカリにバラそうと思( うんだ!!」- “I think I will reveal to Hikari that I'm just pretending to be a delinquent!”
不自然 (Unnatural)
不自然
It combines 不 (not) with 自然 (natural) to show what is not natural.

The Detective Boys group visits a cabin where Professor Agasa has secretly set out clues leading to a treasure. Conan draws the group’s attention to an arrow pointing to a table, on top of which there is…
- コナン:
- 「これまた不自然
( に散( らばったトランプの山( …」- “A pile of cards, rather unnaturally scattered about.”
- 「しかも、なぜかスペードのAだけが画鋲
( でとめてある…」- “Further, for some reason, only the ace of spades is pinned down with thumbtacks...”
- “A pile of cards, rather unnaturally scattered about.”
States of Uncertainty
不思議 (Mystery)
不思議
It combines 不 (not) with 思議 (ordinary reasoning) to show something beyond easy explanation.

Evidence piles up for Ran that Conan, the smart young boy staying with her family, may actually be Shin’ichi, her missing childhood friend. She’s convinced that he’s Shin’ichi on the inside, but the sticking point is how he went from being a teenager to a child.
- 欄
( : - 「SF
( じゃあるまいし…」- “It's not like this is sci-fi.”
- 「こんな不思議
( な事( ってありえない…」- “Such an incredible thing is inconceivable...”
- “It's not like this is sci-fi.”
不意 (Unexpected)
不意
It combines 不 (not) with 意 (intention) to show something outside what was intended.

During a training session, Tsubaki quickly subdues Asagao. Sazanka uses this opportunity to launch a surprise attack, only for Tsubaki to anticipate it and take her down as well.
- ツバキ:
- 「不意
( をつくばかりじゃダメです。」- “You can't rely just on surprise attacks.”
- 「基本
( があるからこそ奇襲( が活( きるんです。」- “It's precisely from having fundamentals that surprise attacks become effective.”
- “You can't rely just on surprise attacks.”
- サザンカ:
- 「はい…」
- “Yeah...”
Tsubaki is teaching that being clever or tricky (using surprise attacks) isn’t enough on its own. True skill comes from mastering the basics first, which then make those surprise moves actually work.