鎌鼬[kamaitachi] type Japanese folkloric monster (yokai), thought to be a trio of weasels who appear in a whirlwind to cut their victim
鼬鼠[itachi] weasel (esp. the Japanese weasel, Mustela itatsi)
鼬ごっこ[itachigokko] doing the same thing repeatedly
鼬の道[itachinomichi] not to write to or visit someone
鼬の最後っ屁[itachinosaigoppe] final emergency measure (lit: the final fart of a weasel)

鼬鮫[itachizame] tiger shark (Galeocerdo cuvier)
黄鼬[ten] Japanese marten (Martes melampus)
毛長鼬[kenagaitachi] polecat (Mustela putorius)
鼬魚[itachiuo] goatsbeard brotula (species of ophidiiform fish, Brotula multibarbata)
朝鮮鼬[chousenitachi] Korean yellow weasel (Mustela sibirica coreana)