Solitary person left flipping US city (5)
I believe the answer is:
loner
'solitary person' is the definition.
(I've seen this before)
'left flipping us city' is the wordplay.
'left' becomes 'l' (common abbreviation).
'flipping' says the letters should be written in reverse.
'us city' becomes 'Reno' (city in Nevada).
'reno' backwards is 'oner'.
'l'+'oner'='LONER'
(Other definitions for loner that I've seen before include "Unaccompanied chap" , "Introvert" , "Solitary person" , "One liking solitude" , "person, one hating company" .)