Hound immoral head of judiciary in Northern Ireland (7)
I believe the answer is:
basenji
'hound' is the definition.
(basenji is a breed of dog)
'immoral head of judiciary in northern ireland' is the wordplay.
'immoral' becomes 'base' (I've seen this in another clue).
'head of' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'northern ireland' becomes 'NI' (abbreviation).
The first letter of 'judiciary' is 'j'.
'j' put within 'ni' is 'nji'.
'base'+'nji'='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" , "Smallish hunting dog" , "Barkless dog" .)