exert
1. [ verb ] put to use
Synonyms: exercise
Examples:

"exert one's power or influence"

Related terms: use use
2. [ verb ] of power or authority
Synonyms: maintain wield
Related terms: have must
3. [ verb ] make a great effort at a mental or physical task
Examples:

"exert oneself"

Related terms: act overexert effort
Similar spelling:   exsert
  exertion
  exhort
  excrete
  excreta