芋虫

Compound of 芋 (imo, “potato, tuber”) +‎ 虫 (mushi, “bug, worm”). Refers specifically to hairless caterpillars, most specifically to varieties that eat the leaves of the 里芋 (sato imo, “taro”) or 薩摩芋 (satsuma imo, “sweet potato”).[1][2][3]

First attested in the Nippo Jisho of 1603.[1][4]

• (Tokyo) いも​むし [ìmóꜜmùshì] (Nakadaka – [2])[5]
• IPA^(key): [imo̞mɯ̟ᵝɕi]

芋(いも)虫(むし) or 芋虫(イモムシ) • (imomushi) 

1. a hairless caterpillar [from 1603]
   • 1999 September 23, “アシッドクロウラー [Acid Crawler]”, in Vol.5, Konami:

     巨(きょ)大(だい)ないもむし。強(きょう)力(りょく)な酸(さん)をはき、何(なん)でも溶(と)かしてしまう。

     Kyodai na imomushi. Kyōryoku na san o haki, nan demo tokashite shimau.

     A gigantic caterpillar. Its acid is so strong it can melt anything.

2. (figurative) an angry person (from the way that a person may puff up when angry and go red and swollen in the face, similar to the defense behaviors of some caterpillars) [from 1690]
3. (figurative, derogatory) a dummy; a term used to ridicule a person [from 1749]
4. a children's song and game, played by everyone squatting and holding onto the waist or shoulders of the person in front, and the whole group trying to move like a caterpillar [from 1830s]

   Synonyms: 芋虫ころころ (imomushi korokoro), 芋虫ごろごろ (imomushi gorogoro)

5. a kind of traditional toy made to look and move like a caterpillar

   Synonyms: 俵転ばし (tawara korobashi), 俵返り (kawaga-gaeri)

• As with many terms that name organisms, this term is often spelled in katakana, especially in biological contexts (where katakana is customary), as イモムシ.

• 毛(ケ)虫(ムシ) (kemushi, “a hairy caterpillar”)