Ewe turns out to be alternative source of milk (3,5)
I believe the answer is:
wet nurse
'be alternative source of milk' is the definition.
I can't tell whether this definition defines the answer.
'ewe turns out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'ewe'+'turns'='eweturns'
'eweturns' with letters rearranged gives 'WET-NURSE'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for wet nurse that I've seen before include "Milk supplier" , "Child-minder" , "feeder" , "someone else to feed baby" , "Woman employed to suckle" .)