人心不足蛇吞象

a man who is never content is like a snake trying to swallow an elephant (idiom)

person; people / CL:個|个[ge4],位[wei4]

popular feeling / the will of the people

heart / mind / intention / center / core / CL:顆|颗[ke1],個|个[ge4]

no; not so / (bound form) not; un-

insufficient / lacking / deficiency / not enough / inadequate / not worth / cannot / should not

excessive

foot / to be sufficient / ample

variant of 蛇[she2]

snake / serpent / CL:條|条[tiao2]

to swallow / to take

elephant / CL:隻|只[zhi1] / shape / form / appearance / to imitate