Back with little daughter's potty (4)
I believe the answer is:
daft
'potty' is the definition.
(I've seen this before)
'back with little daughter's' is the wordplay.
'back' becomes 'aft' ('aft' is associated in meaning with 'back'**).
'with' says to put letters next to each other.
'little' says to take the initial letters.
The first letter of 'daughters' is 'd'.
'aft' put after 'd' is 'DAFT'.
(Other definitions for daft that I've seen before include "Informally silly or crazy" , "Potty" , "Scatty" , "like a brush?" , "Idiotic" .)