Got a new dress (4)
I believe the answer is:
toga
'dress' is the definition.
(I have seen 'Roman dress ' mean 'toga' so perhaps 'dress' could also mean 'toga')
'got a new' is the wordplay.
'new' indicates anagramming the letters.
'got'+'a'='gota'
'gota' anagrammed gives 'TOGA'.
(Other definitions for toga that I've seen before include "Old-style dress" , "Sheet draped round Roman" , "Roman tunic" , "garment of old" , "Robe worn by Caesar" .)