Help returning, not applicable to goddess (5)
I believe the answer is:
diana
'to goddess' is the definition.
(Roman goddess)
'help returning not applicable' is the wordplay.
'help' becomes 'aid' (synonyms).
'returning' says the letters should be written in reverse.
'not applicable' becomes 'na' (this could be a standard abbreviation of which I'm unaware).
'aid' reversed gives 'dia'.
'dia'+'na'='DIANA'
Can you help me to learn more?
(Other definitions for diana that I've seen before include "She separated from Charles" , "female" , "Woman" , "Roman godess of the hunt" , "Roman goddess of the moon and the hunt" .)