Jockey married fan (7)
I believe the answer is:
'fan' is the definition.
(an admirer is a fan of something)
'jockey married' is the wordplay.
'jockey' indicates anagramming the letters (the letters scramble or jockey around).
'married' anagrammed gives 'ADMIRER'.
(Other definitions for admirer that I've seen before include "Married to one who cherishes" , "girlfriend?" , "Hopeful lover?" , "Supporter or suitor" , "Romantic adorer" .)