杞人憂天

1. • like the man of 杞 qǐ who feared the sky would fall (idiom)

     lit.

2. • to entertain groundless fears

     fig.

Character by character

• 杞(qǐ)Qi, a Zhou Dynasty vassal state
• 人(rén)person
• 憂(yōu)worry
• 天(tiān)day