Pretty clothing line's pizzazz (5)
I believe the answer is:
flair
'pizzazz' is the definition.
(I've seen this in another clue)
'pretty clothing line's' is the wordplay.
'pretty' becomes 'fair' (both can mean beautiful or attractive).
'clothing' indicates putting letters inside (some letters cover up or clothe others).
'line' becomes 'l' (used when specifying particular lines from a poem).
'fair' placed around 'l' is 'FLAIR'.
(Other definitions for flair that I've seen before include "Natural talent or panache" , "Taste" , "Style, talent" , "Faculty" , "Natural talent and aptitude" .)