Appreciate fashionable pleat (8)
I believe the answer is:
increase
'appreciate' is the definition.
(thesaurus)
'fashionable pleat' is the wordplay.
'fashionable' becomes 'in' (in can mean fashionable or trendy).
'pleat' becomes 'crease' (crease in a skirt).
'in'+'crease'='INCREASE'
(Other definitions for increase that I've seen before include "Wax" , "Grow, add to" , "boost" , "Grow, expand" , "Amplification" .)