agonize

Concise Oxford English Dictionary © 2008 Oxford University Press:
agonize /ˈaɡənʌɪz/ (or agonise)

▶verb

• 1 undergo great mental anguish through worrying over something.

• 2 (usu. as adj. agonizing) cause agony to.

– derivatives
agonizingly adverb.

– origin C16: from Fr. agoniser or late L. agonizare, from Gk agōnizesthai ‘contend’, from agōn ‘contest’.