Thanks, thanks again, bye! (2-2)
I believe the answer is:
ta-ta
'again bye' is the definition.
The definition suggests a singular noun which matches the answer.
'thanks thanks' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'thanks' becomes 'ta' (UK informal version of 'thank you').
'ta'+'ta'='TA-TA'
Can you help me to learn more?
(Other definitions for ta-ta that I've seen before include "Adieu" , "Bye!" , "A Farewell" , "Cheerio" , "Bye-bye" .)