逆流溯源

to go back to the source

contrary / opposite / backwards / to go against / to oppose / to betray / to rebel

against the stream / adverse current / a countercurrent / fig. reactionary tendency / to go against the trend

to flow / to disseminate / to circulate or spread / to move or drift / to degenerate / to banish or send into exile / stream of water or sth resembling one / class, rate or grade

to go upstream / to trace the source

variant of 溯[su4]

to investigate the origin of sth / to trace a river upstream back to its source

root / source / origin