ordeal

Concise Oxford English Dictionary © 2008 Oxford University Press:
ordeal/ɔːˈdiːl/

▶noun

• 1 a prolonged painful or horrific experience.

• 2 an ancient test of guilt or innocence by subjection of the accused to severe pain, survival of which was taken as divine proof of innocence.

– origin OE ordāl, ordēl, of Gmc origin, from a base meaning ‘share out’.