Hound is, by itself, endearing (9)
I believe the answer is:
persecute
'hound' is the definition.
(I've seen this before)
'by itself endearing' is the wordplay.
'by itself' becomes 'per se' (I've seen this in another clue).
'endearing' becomes 'cute' (I've seen this before).
'perse'+'cute'='PERSECUTE'
'is' acts as a link.
(Other definitions for persecute that I've seen before include "Harass for reasons of politics, religion etc" , "victimise" , "Oppress, cause to suffer" , "hound" , "Dog" .)