Sentence:  In California a senior companion offered to demonstrate to his new <WSD>greenie</WSD> how he succeeded in placing Books of Mormon in people′s houses. The two of them knocked on a door. A woman answered, and the senior companion threw a book past her into the house and then ran, leaving the <WSD>greenie</WSD> to stammer out an explanation to the irate woman. 
Meaning of the word marked with <WSD> tags:  A beginner, a novice.