English edit

Etymology edit

From non- +‎ optional.

Adjective edit

non-optional (not comparable)

  1. Alternative form of nonoptional.
    • 2020 December 2, Mark Smith, “Why fares reform is essential... and why it won't be easy”, in Rail, pages 34–35:
      BR offered discounts on round trips to encourage optional days out and weekends away, but it did not want to discount one-way tickets which were typically used for non-optional journeys.