Fig. a favored person. (Not necessarily young or a boy.) The teacher's fair-haired boy always does well on tests.The supervisor's son was the fair-haired boy on the construction site.
A favorite, a person who is given special treatment. For example, Today the attorney general is the governor's fair-haired boy. This term alludes to the preference of blond ("fair") hair over dark hair. [Late 1800s]
n. a promising young man; a young man who receives favoritism. Ted is the boss’s fair-haired boy now, but he’ll be just like the rest of us in a month.