Two scams a realtor's offering? (5)
I believe the answer is:
condo
'a realtor's offering?' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'two scams' is the wordplay.
'two scams' means two replacements for 'scam'.
'scam' becomes 'con' (both can mean a fraudulent scheme).
'scam' becomes 'do' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'con'+'do'='CONDO'
Can you help me to learn more?
(Other definitions for condo that I've seen before include "Apartment in North America" , "apartment block in Toronto" , "accommodation out west" , "American apartment" , "Texan dwelling" .)