Fit patient, carrier (8)
I believe the answer is:
suitcase
'carrier' is the definition.
'fit patient' is the wordplay.
'fit' becomes 'suit' (synonyms).
'patient' becomes 'case' (synonyms).
'suit'+'case'='SUITCASE'
(Other definitions for suitcase that I've seen before include "Item of luggage" , "Form of luggage" , "Type of holdall" , "one taken on holiday" , "one taken away?" .)