groupie; groupy
noun
1
a girl who trades her sexual availability to rock groups and musicians in exchange for hanger-on status US, 1966.
2
a follower or hobbyist devoted to a pre-eminent person within a given field, or to a genre or subject type. An extension of the previous sense, this usage is not restricted to rock groups or music, nor is there a suggestion that sex is a prerequisite; the tone may be derogatory, jocular or ironic US, 1967