Literally "the old man on the frontier loses his horse"; an idiom suggesting that misfortune may be a blessing in disguise, or vice versa. It describes how disaster and good fortune can alternate or transform into one another, emphasizing that one should not judge events based only on their immediate impact

(literary) how can one know; how is it possible to know

to not be; to not belong to; equivalent to 是 shì in its negative form

good fortune; happiness; luck; blessing; a state of well-being, often used in contrast to 祸 huò or as a specific opportunity from fate like 口福 kǒu​fú