Sweet American pin-up with mostly pleasant clothing (7)
I believe the answer is:
angelic
'sweet' is the definition.
(synonyms)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for angelic that I've seen before include "Virtuous" , "sweet-natured too" , "in the manner of Gabriel?" , "Exceptionally innocent" , "Sweet and well-behaved" .)