One in vehicle with nothing from capital (5)
I believe the answer is:
cairo
'capital' is the definition.
(capital of Egypt)
'one in vehicle with nothing' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' is an insertion indicator.
'vehicle' becomes 'car' (car is a kind of vehicle).
'with' is a charade indicator (letters next to each other).
'nothing' becomes 'O' (looks like zero - 0).
'i' placed into 'car' is 'cair'.
'cair'+'o'='CAIRO'
'from' acts as a link.
(Other definitions for cairo that I've seen before include "Port upstream from the Nile delta" , "Egyptian capital" , "Al Qahira" , "City near the Nile delta" , "African city" .)