overextend
1. [ verb ] strain excessively
Synonyms: overstrain
Examples:

"He overextended himself when he accepted the additional assignment"

Related terms: strain overstrain
Similar spelling:   overexcited
  overexert
  Overstreet
  overspend
  overexpose
  oversee
  overstretch
  overexploit
  overstep
  overspread
  overgreedy
  oversewn
  overreact
  overexposure
  overexertion
  overeager
  overstress
  overstate