前功盡棄

to waste all one's previous efforts (idiom) / all that has been achieved goes down the drain

front / forward / ahead / first / top (followed by a number) / future / ago / before / BC (e.g. 前293年) / former / formerly

meritorious deed or service / achievement / result / service / accomplishment / work (physics)

to use up / to exhaust / to end / to finish / to the utmost / exhausted / finished / to the limit (of sth) / all / entirely

to abandon / to relinquish / to discard / to throw away