Cathy's new boat (5)
I believe the answer is:
yacht
'boat' is the definition.
(yacht is a type of boat)
'cathy's new' is the wordplay.
'new' is an anagram indicator.
'cathy' is an anagram of 'YACHT'.
(Other definitions for yacht that I've seen before include "Fast sailing vessel" , "Sailing or motor vessel for cruising or racing" , "Pleasure-boat" , "Type of boat" , "Sailing boat" .)