Dog returns to supreme being (3)
I believe the answer is:
god
'supreme being' is the definition.
(synonyms)
'dog returns' is the wordplay.
'returns' shows that the letters should be reversed in order.
'dog' reversed gives 'GOD'.
'to' is the link.
(Other definitions for god that I've seen before include "eg Cupid" , "Divinity" , "Mars or Mercury, say" , "Supreme being" , "Eg, Quetzalcoatl" .)