a purposeful or industrious undertaking (especially one that requires effort or boldness)
"he had doubts about the whole enterprise"
A sincere attempt; a determined or assiduous effort towards a specific goal; assiduous or persistent activity.
"The team's relentless training regimen was a true endeavor to master the complex new technique before the championship."
In plain English: An endeavor is an attempt to do something difficult that requires effort and determination.
"She made every endeavor to finish her homework before dinner."
Usage: Use "endeavor" as a noun in formal contexts, but prefer the more casual "effort" or "attempt" for everyday speech. Avoid using it to describe trivial tasks where these simpler synonyms convey the intended meaning better.
To exert oneself.
"She endeavored to lift the heavy box despite her exhaustion."
The word entered English from the phrase "in duty," combining in with a form of Middle Dutch or Low German for obligation. Originally meaning to make an effort as one's specific duty, it evolved into its current sense through this direct translation of French legal and moral concepts.