The Collaborative International Dictionary of English v.0.48:
Endeavor \En*deav"or\, v. t. [imp. & p. p. Endeavored; p. pr.
& vb. n. Endeavoring.] [OE. endevor; pref. en- + dever,
devoir, duty, F. devoir: cf. F. se mettre en devoir de faire
quelque chose to try to do a thing, to go about it. See
Devoir, Debt.] [Written also endeavour.]
To exert physical or intellectual strength for the attainment
of; to use efforts to effect; to strive to achieve or reach;
to try; to attempt.
It is our duty to endeavor the recovery of these
beneficial subjects. --Ld. Chatham.
To endeavor one's self, to exert one's self strenuously to
the fulfillment of a duty. [Obs.] "A just man that
endeavoreth himself to leave all wickedness." --Latimer.