Her event unravelled, attracting fewer still (12)
I believe the answer is:
nevertheless
'still' is the definition.
(I've seen this before)
'her event unravelled attracting fewer' is the wordplay.
'unravelled' is an anagram indicator.
'attracting' means one lot of letters go next to another.
'fewer' becomes 'less' ('less' is associated in meaning with 'fewer').
'her'+'event'='herevent'
'herevent' is an anagram of 'neverthe'.
'neverthe'+'less'='NEVERTHELESS'
(Other definitions for nevertheless that I've seen before include "However" , "Still" , "In spite of everything" , "Notwithstanding" , "But always" .)