demon

1. Origins, structure, and basic meaning

• Structure: 鬼 denotes an ogre or demon in Japanese folklore; its on-reading is き, and its kun-reading is おに.
• Basic usage: Standalone 鬼 refers to an ogre or demon, while 鬼ごっこ is the fixed name for a game of tag.

2. Common pitfalls and similar expressions

• 鬼 / 鬼ごっこ
  • 鬼: This noun refers to a horned ogre in a folktale or to a mask representing one. Example: 昔話では角の生えた鬼が山に住んでいる。
  • 鬼ごっこ: This word refers to tag, a game in which children chase and avoid one another. Example: 子どもたちは公園で鬼ごっこをして遊んだ。