Chinese

		cliff; precipice	to rein in one's horse
trad. (懸崖勒馬)		懸崖	勒馬
simp. (悬崖勒马)		悬崖	勒马
Literally: “to rein in the horse at the edge of the precipice”.

Idiom

懸崖勒馬

1. to act in the nick of time; to wake up to danger at the last moment