Italian lady returning an unspoken acknowledgement (5)
I believe the answer is:
donna
'italian lady' is the definition.
('lady' in Italian)
'returning an unspoken acknowledgement' is the wordplay.
'returning' shows that the letters should be reversed in order.
'unspoken acknowledgement' becomes 'nod' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'an'+'nod'='annod'
'annod' written backwards gives 'DONNA'.
Can you help me to learn more?
(Other definitions for donna that I've seen before include "Girl" , "Title of Spanish or Portuguese lady" , "Spanish lady's title" , "See 10" , "Title of Spanish or Italian lady" .)