A favela harbouring Yankee finding refuge (6)
I believe the answer is:
asylum
'refuge' is the definition.
('asylum' can be a synonym of 'refuge')
'a favela harbouring yankee' is the wordplay.
'favela' becomes 'slum' (both can mean a poor town or neighbourhood).
'harbouring' indicates putting letters inside.
'yankee' becomes 'y' (phonetic alphabet: alpha, bravo, charlie etc.).
'slum' going around 'y' is 'sylum'.
'a'+'sylum'='ASYLUM'
'finding' acts as a link.
(Other definitions for asylum that I've seen before include "A shelter from danger or hardship" , "Sanctuary or institution for mentally ill" , "Place of refuge, once a mental institution" , "find sanctuary there" , "Shelter given to refugee" .)