The term 'prodigal one' is a biblical reference to the parable of the prodigal SON, which tells the story of a young man who leaves his father's house and squanders his inheritance. The crossword solutions for this term are 'WASTREL' (7 letters) and 'SON' (3 letters). A WASTREL is someone who is wasteful and irresponsible with money or resources, which is an apt description of the prodigal SON in the parable. The solution 'SON' is also fitting, as it refers to the protagonist of the parable.