noun
undercurrent; hidden current
Refers to a current flowing beneath the surface of water, often used metaphorically for hidden social or political trends.
この海域には危険な暗潮がある。
There is a dangerous undercurrent in this sea area.
政治の世界では、さまざまな暗潮が動いている。
In the world of politics, various undercurrents are at work.