杞人之忧

qǐ rén zhī yōu

lit. the fear held by a man of 杞[Qi3] that the sky would fall (idiom)

fig. groundless fears

杞

qǐ

willow

人

rén

person; people

之

zhī

(possessive particle, literary equivalent of 的[de5])

忧

yōu

to worry