Fleet attack round the capital of Peru (5)
I believe the answer is:
rapid
'fleet' is the definition.
(I've seen this before)
'attack round the capital of peru' is the wordplay.
'attack' becomes 'raid' (raiding is a kind of attacking).
'round' means one lot of letters goes inside another.
'the capital of' suggests taking the first letters.
The first letter of 'peru' is 'p'.
'raid' placed around 'p' is 'RAPID'.
(Other definitions for rapid that I've seen before include "Happening at great speed" , "Showing pace" , "Precipitate" , "Zippy" , "Swift, speedy" .)