Its good to have a dress (4)
I believe the answer is:
gown
'a dress' is the definition.
(I know this)
'its good to have' is the wordplay.
I cannot really see how this works, but
'good' could be 'g' (abbreviation) and 'g' is present in the answer.
'have' could be 'own' (to have something is to own it) and 'own' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for gown that I've seen before include "Academic or formal wear" , "Formal frock, hospital garb and ceremonial dress" , "Woman's long dress or judge's robe" , "Ball dress" , "Loose flowing garment for woman or judge" .)