undercurrent
noun [ C ] uk/ˈʌn.dəˌkʌr.ənt/ us/ˈʌn.dɚˌkɝː.ənt/
（通常指负面的或危险的）潜在的情绪（或思想等）
an emotion, belief, or characteristic of a situation that is hidden and usually negative or dangerous but that has some effect
undercurrents of racism/anxiety/violence 潜在的种族主义／焦虑／暴力
Beneath the smooth surface of political life, there are powerful and dangerous undercurrents. 在日常政治生活平静的表面下存在着强大而危险的潜流。