Whimsically put animal's appendage back on sale (6)
I believe the answer is:
retail
'sale' is the definition.
(I have seen 'Sale of goods ' mean 'retail' so perhaps 'sale' could also mean 'retail')
'whimsically put animal's appendage back on' is the wordplay.
I cannot quite see how this works, but
'appendage' could be 'tail' (tail is a type of bodily appendage) and 'tail' is present in the answer.
'on' could be 're' (regarding) and 're' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for retail that I've seen before include "Relate details" , "This trade serves the general public" , "Narrate or sell to public" , "The selling of goods to consumers" , "The trade serving the public" .)