Merriam-Webster Collegiate Dictionary - endeavor

 I. verb  (~ed; ~ing)  Etymology: Middle English endeveren to exert oneself, from en- + dever duty — more at devoir  Date: 15th century  transitive verb  1. archaic to strive to achieve or reach  2. to attempt (as the fulfillment of an obligation) by exertion of effort ~s to finish the race  intransitive verb to work with set purpose  Synonyms: see attempt  II. noun  Date: 15th century  1. serious determined effort  2. activity directed toward a goal ; enterprise fields of ~