Stagger round the capital of Portugal and drive back (5)
I believe the answer is:
repel
'drive back' is the definition.
(synonyms)
'stagger round the capital of portugal' is the wordplay.
'stagger' becomes 'reel' (both can mean to move around without balance).
'round' means one lot of letters goes inside another.
'the capital of' indicates taking the first letters.
The initial letter of 'portugal' is 'p'.
'reel' going around 'p' is 'REPEL'.
'and' acts as a link.
(Other definitions for repel that I've seen before include "may turn your stomach" , "Turn away" , "Sicken" , "Fend off" , "Drive away like leper" .)