Deighton, Irish specialist, is compassionate (7)
I believe the answer is:
lenient
'is compassionate' is the definition.
(I've seen this before)
'deighton irish specialist' is the wordplay.
'deighton' becomes 'len' (I've seen this in another clue).
'irish' becomes 'i' (this might be a standard abbreviation which I don't know about).
'specialist' becomes 'ent' (Ear, Nose and Throat specialist).
'len'+'i'+'ent'='LENIENT'
Can you help me to learn more?
(Other definitions for lenient that I've seen before include "'Indulgent, easy (7)'" , "Tolerant, merciful" , "Not severe in punishing" , "Soft on the rules" , "Compassionate" .)