Meaning
The kanji 朽 (kuchiru) primarily means “to rot,” “to decay,” “to spoil,” “to perish,” or “to deteriorate.” While often describing the breakdown of organic matter like wood or food, its usage extends metaphorically. It can refer to abstract concepts such as a fading reputation, obsolescent customs, or talent that diminishes over time. Essentially, 朽 captures the essence of losing original form, strength, or vitality, often due to time or environmental factors. This leads to eventual disintegration or obsolescence.
The kanji's etymology provides clues to its meaning. 朽 is a phono-semantic compound, made up of two main components. The left radical, 木 (ki), means “tree” or “wood,” clearly pointing to the organic materials often associated with decay. The right component, 丂 (kyuu or kō), serves primarily as a phonetic element, giving it the “kyuu” sound in its on'yomi. Visually, 丂 can also be interpreted as a bent or broken line, subtly suggesting something that is no longer straight, firm, or intact—a hint at breaking down or weakening. Therefore, the combination of 木 (wood) and 丂 (bent/broken/declining) visually and semantically reinforces the concept of organic material decaying, breaking apart, and becoming rotten. This visual connection makes the kanji's meaning quite intuitive for learners.
The kanji 朽 has 6 strokes and is a Joyo kanji, indicating it's part of the standard set for general use. While it doesn't have an elementary school grade assigned (hence 'null' for grade), learners typically encounter it at advanced stages. This aligns with its JLPT N1 classification, reflecting its nuanced usage in formal and literary contexts.
Readings
On'yomi (音読み) — Chinese-derived readings
The primary on'yomi for 朽 is キュウ (Kyuu). This reading originates from ancient Chinese pronunciations and primarily appears in formal compound words, often academic or literary. These compounds frequently denote abstract concepts like decay, imperishability, or dilapidation. Their meaning often extends beyond mere physical rotting to encompass moral or historical contexts.
- 不朽 (fukyuu) — This compound means immortality, imperishability, or everlasting. It signifies something that will never decay or be forgotten, such as a timeless work of art, a heroic deed, or an enduring legacy.
例：その作家の作品は不朽の名作として語り継がれている。
- 朽廃 (kyuuhai) — Meaning dilapidation, decay and ruin, often used to describe buildings, structures, or even systems that have fallen into a state of severe disrepair.
例：長年放置された家屋は朽廃が進んでいた。
- 腐朽 (fukyuu) — This term refers to decay or putrefaction, commonly used for the biological decomposition of organic matter, similar to 朽 itself but often with a stronger emphasis on microbial action.
例：木材の腐朽は湿気によって早まる。
Kun'yomi (訓読み) — Native Japanese readings
The main kun'yomi for 朽 is くちる (ku.chiru), an intransitive verb. This is the most direct and common native Japanese reading to express the act of rotting, decaying, spoiling, or perishing. It applies broadly to physical objects like wood, food, or buildings, as well as to abstract concepts such as reputation, traditions, or skills that fade away or become obsolete.
- 朽ちる (kuchiru) — The base verb meaning to rot, decay, spoil, or perish. It signifies a gradual process of deterioration.
例：時間とともに、古い木造の橋は朽ちていく。
- 朽木 (kuchiki) — This compound literally means "rotten wood" or "deadwood." It can also be used metaphorically to describe someone useless or talentless.
例：森の中には、朽木が多く散乱していた。
- 朽ち果てる (kuchihateru) — A stronger, more emphatic verb meaning to rot away completely, to perish entirely, or to be utterly ruined. The suffix 果てる (hateru) adds the nuance of reaching an ultimate end.
例：無人の廃墟は時間とともに朽ち果てていった。
Common Words & Compounds
The kanji 朽 appears in a variety of words and compounds, demonstrating its versatile application across different contexts. It ranges from literal decay to metaphorical impermanence and immortality. Here are some key examples:
General Decay and Deterioration
- 朽ちる (kuchiru) — To rot, decay, spoil. This is the fundamental verb used to describe the process of organic or structural breakdown.
- 朽木 (kuchiki) — Rotten wood, deadwood. Often found in forests, it's also a metaphor for someone useless or without talent.
- 朽ち果てる (kuchihateru) — To rot away completely, to perish utterly. This emphasizes a complete and irreversible state of decay.
- 朽ちかけた建物 (kuchikaketa tatemono) — A decaying building, a building on the verge of collapse due to rot.
Preservation and Immortality
- 不朽 (fukyuu) — Immortality, imperishability, everlasting. This powerful word describes things that transcend decay and the passage of time.
- 不朽の名作 (fukyuu no meisaku) — An immortal masterpiece. A work of art or literature that endures through generations.
- 不朽の功績 (fukyuu no kōseki) — An imperishable achievement. A lasting contribution or accomplishment.
Advanced and Abstract Concepts
- 朽廃 (kyuuhai) — Dilapidation, decay and ruin. Often used for infrastructure or large structures, it signifies a state of severe breakdown.
- 腐朽 (fukyuu) — Decay, putrefaction. While similar to 朽, 腐朽 often carries a stronger connotation of biological decomposition, especially by microorganisms.
- 朽ちる運命 (kuchiru unmei) — This phrase expresses the inevitable decline of something.
- 栄華は必ず朽ちる (eiga wa kanarazu kuchiru) — Glory will inevitably perish. A philosophical saying about the transient nature of worldly power and splendor.
Example Sentences
Here are some example sentences demonstrating the practical usage of 朽 in various contexts.
長年放置された木材は雨風で徐々に朽ちていった。
Naganen hōchi sareta mokuzai wa amekaze de jojo ni kuchite itta.
The lumber left for many years gradually rotted away due to the rain and wind.
朽木は燃えやすいが、燃料としてはすぐに灰になる。
Kuchiki wa moe yasui ga, nenryō to shite wa sugu ni hai ni naru.
Rotten wood burns easily but quickly turns to ash as fuel.
彼の不朽の功績は、歴史の中に確かに刻まれている。
Kare no fukyuu no kōseki wa, rekishi no naka ni tashika ni kizamarete iru.
His imperishable achievement is certainly carved into history.
手入れされていない古い神社は軒が朽ちはじめていた。
Teire sarete inai furui jinja wa noki ga kuchi hajimete ita.
The eaves of the old, neglected shrine had begun to rot.
どんなに偉大な帝国も、いつかは朽ち果てる運命にある。
Donna ni idai na teikoku mo, itsuka wa kuchihateru unmei ni aru.
No matter how great an empire, it is fated to eventually perish completely.
腐朽を防ぐために、木造建築には防腐剤が必要だ。
Fukyuu o fusegu tame ni, mokuzō kenchiku ni wa bōfuzai ga hitsuyō da.
To prevent decay, preservatives are necessary for wooden architecture.
彼の名声は時間が経っても朽ちることなく、輝き続けた。
Kare no meisei wa jikan ga tattemo kuchiru koto naku, kagayaki tsuzuketa.
His reputation did not perish with time, but continued to shine.
朽廃した工場は、かつての繁栄の名残を留めていた。
Kyuuhai shita kōjō wa, katsute no han'ei no nagori o todomete ita.
The dilapidated factory still retained vestiges of its former prosperity.
昔ながらの伝統が時代とともに朽ちていくのは寂しいことだ。
Mukashi nagara no dentō ga jidai to tomo ni kuchite iku no wa sabishii koto da.
It's sad that old traditions decay with the times.
Memory Tip
To remember the kanji 朽, visualize its components. On the left, 木 (ki) depicts a 'tree' or 'wood,' immediately establishing the context of organic matter. On the right, 丂 (kyuu), while primarily phonetic, visually resembles a bent or broken stick, or even a nail sticking out at an angle. Picture a neglected tree (木); its wood starts to bend and break (丂), becoming rotten and unusable. You can envision a dead tree in a forest, its branches no longer strong and straight but instead beginning to splinter and droop, illustrating its decay. This 'tree' is literally falling apart, rotting or perishing due to time and the elements. This vivid image of a decaying, broken tree helps cement 朽's meaning: 'to rot' or 'to decay.'