Walk dogs, perhaps in retirement (4)
I believe the answer is:
step
'walk' is the definition.
(I know this)
'dogs perhaps in retirement' is the wordplay.
'dogs perhaps' becomes 'pets' (dogs are often kept as pets).
'in retirement' says the letters should be written in reverse (retire can mean to go back or backwards).
'pets' reversed gives 'STEP'.
(Other definitions for step that I've seen before include "Indian garment" , "little walk?" , "Bit of mashed potato maybe" , "Pace for a pest" , "Stride" .)