Cardinal left ship somewhere in Florida (3,5)
I believe the answer is:
key largo
'somewhere in florida' is the definition.
(I know that Key Largo is in Florida)
'cardinal left ship' is the wordplay.
'cardinal' becomes 'key' (synonyms).
'left' becomes 'l' (common abbreviation).
'ship' becomes 'Argo' (ship in Greek myth).
'key'+'l'+'argo'='KEY LARGO'
(Other definitions for key largo that I've seen before include "island" , "parts here for 1a and 9 [BACALL & BOGART] - with 12a" , "film" .)