eager, avid, keen, anxious, athirst mean moved by a strong and urgent desire or interest. eager implies ardor and enthusiasm and sometimes impatience at delay or restraint.
//eager to get started avid adds to eager the implication of insatiability or greed.
//avid for new thrills keen suggests intensity of interest and quick responsiveness in action.
//keen on the latest fashions anxious emphasizes fear of frustration or failure or disappointment.
//anxious not to make a social blunder athirst stresses yearning but not necessarily readiness for action.
//athirst for adventure

eager, anxious, and keen mean having or showing a strong desire or interest. eager is used when there is much enthusiasm and often impatience.
//Eager travelers waited for their train. anxious is used when there is fear of failure or disappointment.
// I was anxious to learn who won. keen is used when there is great interest and readiness to act.
// The new scouts are keen to learn.