imponderable

/ɪmˈpɑndərəbəl/
noun
  1. Something that is difficult or impossible to measure, predict, or fully understand.
    • The success of a new product involves imponderables such as public taste and timing.
    • When planning a trip, weather is always an imponderable that can change everything.
    • The outcome of the election depends on many imponderables, like voter turnout.
adjective
  1. Difficult or impossible to measure, predict, or fully understand.
    • The long-term effects of the new policy are imponderable at this point.
    • The artist's inspiration remains an imponderable mystery to critics.
    • She faced an imponderable choice between two equally good job offers.