A put-down for a boy who is less "boyish" than his companions would like. A boy who does not do "boyish" things like play sports, play with bugs or the like. Has nothing to do with gay or homosexual. 1950's slang; ages 8 to 15 and adults from that timeframe. "little fairyhopper" and "great big fairyhopper" both mean the same. Fairy + grasshopper.
"Oh look at Jimmy. He doesn't wanna go play by the tracks: Wassametter; Mommy won't let you go? Wotta little fairyhopper!" "C'mon Bobby, don't be a great big fairyhopper!"