Admirer of lilac originally in bloom (8)
I believe the answer is:
follower
'admirer' is the definition.
(thesaurus)
'of lilac originally in bloom' is the wordplay.
'originally' says to take the initial letters.
'in' is an insertion indicator.
'bloom' becomes 'flower' (synonyms).
The initial letters of 'of lilac' is 'ol'.
'ol' placed into 'flower' is 'FOLLOWER'.
(Other definitions for follower that I've seen before include "A devotee or a pursuer" , "A loyal adherent - or a pursuer" , "Person who succeeds" , "Supporter" , "fan" .)