general situation; general trend; general tendency; way things are moving; current (of the times); tide (e.g. of public opinion)
「大勢」 has another reading with different meanings.
選挙の大勢はもう決まったようだ。
The general outcome of the election seems decided.
大勢に逆らっても結果は変わらない。
Going against the trend won't change the outcome.
世界の大勢をしっかり見極めてから判断するべきだ。
You should carefully assess the global trend before making a judgment.