乘人之危
chéng rén zhī wēi · HSK 7
to take advantage of sb's precarious position
🦅😰 cheng ren zhi wei = ride + person + s + danger — swoop on someone in peril
A vulture-like move: you mount (乘) a person (人) right at the point (之) of their danger (危). The four characters literally spell out exploiting someone whose position is already precarious.
乘 — person 人 atop tree 木 with two feet
Originally a pictograph showing a person standing on a tree, depicting climbing or mounting. The meaning extended from 'to mount/climb' to 'to ride' (a vehicle or animal), and later to 'multiply' in mathematics. The reading shèng (fourth tone) preserves the older sense of a chariot or vehicle.
人 — pictograph of a standing person
人 is a pictograph showing a person viewed from the side, with two strokes representing the legs and torso of a standing human. In oracle bone script it clearly depicted a figure leaning slightly forward. The meaning has remained 'person' or 'human' throughout its history.
之 — foot 止 above ground line 一
Originally a pictograph of a foot (止) stepping forward from a baseline, meaning 'to go' or 'to proceed'. Over time the concrete 'going' sense faded, and 之 was borrowed as a grammatical particle marking possession ('of') or as a pronoun ('it'), which became its dominant use in Classical Chinese.