Striking and elegant but for pants (13)
I believe the answer is:
unforgettable
'striking' is the definition.
(I've seen this before)
'elegant but for pants' is the wordplay.
'pants' indicates an anagram (UK informal term for 'nonsense' or 'rubbish').
'elegant'+'but'+'for'='elegantbutfor'
'elegantbutfor' is an anagram of 'UNFORGETTABLE'.
'and' is the link.
(Other definitions for unforgettable that I've seen before include "Noteworthy" , "Nat King Cole number" , "Always remaining in the mind" , "Striking" , "stuck in my brain?" .)