费尽心思 Traditional 費盡心思 fèi jìn xīn si 🔊 to rack one's brains (idiom) + Keep this word Meanings fèi jìn xīn si 費盡心思 to rack one's brains (idiom); to take great pains to think sth through Its characters 费fèito costHSK 4尽jìnto use upHSK 6心xīnheartHSK 4思sīto think