also: ちえぼとり
noun
unexplained infant fever; teething fever
Historically believed to be linked to intellectual development; now used for unexplained fevers in infants, often around teething age.
赤ちゃんが急に熱を出したけど、知恵熱かもしれない。
The baby suddenly got a fever, but it might be teething fever.
noun
fever from overthinking
Colloquial, often humorous; refers to a slight fever or feeling unwell after intense mental effort, like studying or working too hard.
試験勉強で知恵熱が出そう。
I think I'm getting a fever from all this exam studying.
Compound of 知恵 (wisdom) and 熱 (fever). The original sense arose from the folk belief that infant fevers were caused by rapid mental development.