/ ɪgˈzɜːʃn; NAmE -ˈzɜːrʃ-/ noun
1.
[ U ] (also ex·er·tions [ pl. ]) physical or mental effort; the act of making an effort :
She was hot and breathless from the exertion of cycling uphill.
He needed to relax after the exertions of a busy day at work.
2.
[ sing. ] the use of power to make sth happen :
the exertion of force / strength / authority