取而代之
qǔ ér dài zhī · HSK 7
to remove and replace
取 take + 而 and + 代 replace + 之 it = take over and replace it
Literally take-and-replace-it: the classical 而 links 取 (take/oust) with 代之 (stand in for it). Used when one thing supplants another, e.g. a new boss taking over from the old.
取 — ear 耳 + hand 又
取 originally depicted a hand (又) grasping an ear (耳), referencing the ancient practice of soldiers cutting off enemies' left ears as proof of kills to claim rewards. The meaning broadened from 'seize/take by force' to the general sense of 'take, get, obtain' used today.
而 — pictograph of beard/whiskers hanging from chin
Originally a pictograph of a beard or facial hair hanging below the chin, visible clearly in oracle bone and bronze script forms. The beard meaning was lost early, and the character was borrowed phonetically to write the grammatical conjunction 'and/but/yet'. This connective use has been standard since classical Chinese.
代 — person radical 亻 + 弋 (stake/dart, phonetic)
代 is a semantic-phonetic compound: 亻 (person) gives the meaning and 弋 supplies the sound. The original sense was one person taking the place of another, which broadened to 'substitute,' 'replace,' and then 'generation' or 'era' — successive groups of people replacing the previous.
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.