strenuous

/ˈstrɛnjuəs/
adjective
  1. Requiring or using great effort or energy.
    • Climbing the mountain was a strenuous activity.
    • She made a strenuous effort to finish the project on time.
    • The doctor advised against strenuous exercise after the surgery.
  2. Showing strong and determined effort; vigorous.
    • Her strenuous objections changed the committee's decision.
    • They faced strenuous opposition from the local community.
    • He was a strenuous supporter of education reform.