the times and circumstances; the course of events; turn of fortune
A yojijukugo referring to the changing nature of the times and the situations they bring, often with a sense of fate or fortune's wheel. Literary and somewhat old-fashioned.
Times and circumstances change, and so does a person's fate.
彼は時世時節をわきまえず、無謀な計画を進めた。
He proceeded with a reckless plan, disregarding the course of events.