n.

1. 努力；費力[U][C]
   She failed to unlock the safe in spite of all her exertions.

   她雖然費盡力氣，仍未能將那保險箱的鎖打開。

   He was painting the gate with exertion.

   他在費力地油漆大門。

2. （能力、權力等的）運用；行使[U]
   Exertion of authority over others is not always wise.

   以權壓人並不總是明智的。