noun
insect; bug; small crawling or flying creature
A broad everyday word for insects and many small creatures people casually call bugs; it can include crickets, moths, and similar creatures without strict biological precision.
庭で見たことのない虫を見つけた。
I found a bug in the garden that I had never seen before.
秋になると、夜に虫の声が聞こえる。
In autumn, you can hear the chirping of insects at night.
noun
worm; roundworm; intestinal worm
Used broadly for worm-like creatures and parasitic worms; it is less technical than terms such as 寄生虫 or 回虫.
検査で犬のお腹に虫がいると分かった。
The test showed that the dog had worms in its stomach.
noun
inner impulse; unconscious feeling; mood-influencing inner presence
Figurative use rooted in the traditional idea of an internal 'insect' affecting feelings, instincts, or moods. It appears mostly in idioms such as 虫が知らせる, 虫の居所が悪い, and 虫を殺す.
See also: 虫を殺す
虫が知らせたのか、急に母に電話したくなった。
Maybe it was a premonition, but I suddenly felt like calling my mother.
虫の居所が悪いのか、今日は部長がずっと不機嫌だ。
The department head seems to be in a bad mood today, as if something is bothering him.
noun
fretfulness; nervous irritability
Old-fashioned or folk-expression use, especially in phrases like 癇の虫, referring to a child's fretfulness, nervousness, or irritability rather than a literal insect.
See also: 虫気
子どもは癇の虫が強く、ちょっとしたことで泣き出した。
The child was very fretful and started crying over the smallest thing.
noun
person devoted to one thing; single-minded enthusiast
Used after a noun in expressions such as 本の虫 or 仕事の虫, meaning someone absorbed in or devoted to that one thing.
See also: 本の虫
妹は本の虫で、休みの日もずっと読んでいる。
My younger sister is a bookworm and reads all day even on her days off.
彼は仕事の虫と言われるほど働く。
He works so much that people call him a workaholic.
noun
valve core
Mechanical term for the small core part of a valve, especially in contexts such as bicycle tire valves. This is a specialized sense unrelated to insects.
自転車のバルブの虫を交換したら、空気漏れが止まった。
After I replaced the bicycle valve core, the air leak stopped.
noun
mushi; hanafuda game with a stripped deck
Only with reading むし
Specialized hanafuda term for a type of game played with a reduced or stripped deck; this sense is usually written in kana.
See also: 虫札
花札の「むし」は、札を抜いた特殊な遊び方だ。
Mushi in hanafuda is a special way of playing with some cards removed.
Outdated traditional kanji form; mainly encountered in old writing, stylized titles, or historical contexts.
A more technical or biological word for insects; 虫 is broader and more everyday, and can include worms or figurative uses.
Means parasite, especially in medical or biological contexts; 虫 can casually refer to worms or parasites but is less precise.
Means a tiny bug and can be used contemptuously for an insignificant person; 虫 itself is neutral unless the context gives it a figurative force.
A fixed expression meaning bookworm; it is a common example of the 'person devoted to one thing' sense of 虫.
むし is a native Japanese word conventionally written 虫. 蟲 is an older/outdated kanji form. The exact historical derivation of the word is uncertain.