Goddess lives and breathes (4)
I believe the answer is:
isis
'goddess' is the definition.
(thesaurus)
'lives and breathes' is the wordplay.
'lives' becomes 'is' ('be' can be a synonym of 'live').
'and' means one lot of letters go next to another.
'breathes' becomes 'is' (I've seen this in other clues).
'is'+'is'='ISIS'
(Other definitions for isis that I've seen before include "Sister of Osiris" , "The upper Thames" , "banker in Oxford" , "Egyptian fertility goddess, mother of Horus" , "Egyptian deity" .)