She delivered relish about one (7)
I believe the answer is:
saviour
'one' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'she delivered relish about' is the wordplay.
I cannot really see how this works, but
'she' could be 'vi' and 'vi' is found in the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is found within the answer.
The remaining letters 'sour' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for saviour that I've seen before include "preservative type" , "Round, flat plate" , "Mankind's deliverer (The Scaffold's Lily 15)" , "Deliverer or redeemer" , "people worship Him" .)