Perfectly fit and well (2,5,2,4)
I think it could be either:
as right as rain
'perfectly fit and well' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for as right as rain that I've seen before include "Perfectly OK" , "Sound" , "quite OK" , "Perfectly fit and well" .)
'perfectly fit and well' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for right as rain that I've seen before include "Perfectly fit and well" , "Very fine" , "perfectly in order" , "In perfect order!" .)