used to indicate that one will continue doing something until it is finished, no matter what
义无反顾, 坚持到底：
the workers would fight to the bitter end.
工人们将战斗到底。
[ORIGIN: perhaps associated with a nautical word bitter denoting the last part of a cable inboard of the BITTS, perhaps influenced by the biblical phrases 'her end is bitter as wormwood'. （Prov. 5:4）.]