Fit female wearing a wonderful flip-flop in America (5-4)
I believe the answer is:
about-face
'flip-flop in america' is the definition.
'about face' can be an answer for 'flip-flop' (thesaurus). I'm not sure about the 'in america' bit.
'fit female wearing a wonderful' is the wordplay.
'fit' becomes 'bout' (I've seen this before).
'female' becomes 'f' (common abbreviation).
'wearing' is an insertion indicator.
'wonderful' becomes 'ace' (ace can informally mean very good).
'bout'+'f'='boutf'
'a'+'ace'='aace'
'boutf' placed inside 'aace' is 'ABOUT-FACE'.
Can you help me to learn more?
(Another definition for about-face that I've seen is " Complete change of opinion or attitude".)