Stop at nothing to get capital (5)
I believe the answer is:
quito
'capital' is the definition.
(capital of Ecuador)
'stop at nothing' is the wordplay.
'stop' becomes 'quit' (synonyms).
'at' means one lot of letters go next to another.
'nothing' becomes 'O' (looks like zero - 0).
'quit'+'o'='QUITO'
'to get' is the link.
(Other definitions for quito that I've seen before include "City" , "Capital of Ecuador" , "S America" , "Ecuadorian capital" .)