crucial

/ˈkrü-shəl/

French, from Latin cruc-, crux cross

adjective

  1. important, significant

  2. important or essential as resolving a crisis : decisive

  3. marked by final determination of a doubtful issue

… what use we make of them will be the crucial question.

She played a crucial role in the negotiations.

acute critical crucial mean of uncertain outcome. acute stresses intensification of conditions leading to a culmination or breaking point. critical adds to acute implications of imminent change, of attendant suspense, and of decisiveness in the outcome.