expression, godan verb (-ru)
rack one's brains; think hard
Idiomatic expression meaning to think very hard or struggle to come up with an idea. Marked as rare, but still understood.
いいアイデアが浮かばなくて、脳みそを絞っている。
I can't come up with a good idea, so I'm racking my brains.
Standard kanji spelling for this idiomatic expression.
Alternate kanji spelling using 味噌 for みそ; less common but still encountered.
Literally 'to wring one's brains', a figurative expression combining 脳みそ (brains) with 絞る (to wring). The exact origin is uncertain, but it follows a common pattern of using physical actions metaphorically for mental effort.