Graduate nurse once, one keeping judge’s dog (7)
I believe the answer is:
basenji
'dog' is the definition.
(basenji is a kind of dog)
'graduate nurse once one keeping judge's' is the wordplay.
'graduate' becomes 'BA' (someone with a Bachelor of Arts degree).
'nurse once' becomes 'SEN' (abbreviation for state-enrolled nurse).
'one' becomes 'i' (Roman numeral).
'keeping' indicates putting letters inside (some letters kept inside).
'judge' becomes 'J' (abbreviation for judge).
'sen'+'i'='seni'
'seni' placed around 'j' is 'senji'.
'ba'+'senji'='BASENJI'
(Other definitions for basenji that I've seen before include "Dog unable to bark" , "Small hunting dog" , "Breed of African hunting dog that rarely barks" , "Barkless dog" , "Smallish hunting dog" .)