Other forms: endeavours, endeavoured, endeavouring
To endeavour is to try hard to achieve something. Endeavour to improve, a worthy endeavour, endeavour to attend.
It is formal to the point of stiffness, which is why it appears in official letters and almost nowhere else in speech. As a noun it means an effort or an undertaking. Note the American spelling endeavor; and that the word comes from a French phrase meaning to put oneself in duty.
1verbendeavourTo try hard to achieve something.
“We endeavour to reply to every customer email within two working days.”
2nouneffortAn effort or undertaking.
“Climbing the mountain without oxygen was a dangerous endeavour.”
Too few real examples of this word to estimate which sense is commonest.
endeavour is an effort.
Also accepted in games: endeavor