What does the word exertion mean?

Usage examples for exertion

  1. Gerard continued to gaze out the window opposite, his expression setting as if under a sudden exertion of self- control. – From the Car Behind by Eleanor M. Ingram
  2. Aware of his condition, by some tremendous exertion of his will, he had flung back the lethargy that held his senses, and recovered his dignity. – The Salamander by Owen Johnson
  3. The search for plunder gave place to the most vigorous exertion to save themselves. – The Pirates Own Book by Charles Ellms