兢
jīng
to be fearful
apprehensive
restrain (克) + restrain (克) = fearful, on edge
克 means to overcome or restrain, and doubling it intensifies the sense of straining against something — walking on eggshells, holding yourself in careful check. The repeated form visually mirrors the doubled tension of anxious vigilance.
克To overcomeSemantic
他做事总是战战兢兢，从不粗心。
tā zuò shì zǒng shì zhàn zhàn jīng jīng, cóng bù cū xīn。
he always does things with great caution and apprehension, never being careless.
她第一次上台表演，心里战战兢兢的。
tā dì yī cì shàng tái biǎo yǎn, xīn lǐ zhàn zhàn jīng jīng de。
performing on stage for the first time, she felt fearful and apprehensive inside.