It's expensive, darling (4)
I believe the answer is:
dear
I believe this clue is a double definition.
'it's expensive' is the first definition.
(similar in meaning)
'darling' is the second definition.
(synonyms)
(Other definitions for dear that I've seen before include "Pricey" , "Beloved - expensive" , "close" , "Darling" , "Expensive -- honey" .)