Copy cat enters answers not fully completed (9)
I believe the answer is:
replicate
'copy cat' is the definition.
'replicate' can be an answer for 'copy' (I've seen this before). I'm not sure about the 'cat' bit.
'enters answers not fully completed' is the wordplay.
'enters' indicates putting letters inside.
'answers' becomes 'replies' (to reply is to give an answer).
'not fully' means to remove the last letter.
'completed' becomes 'cat' (I can't justify this - if you can you should give a lot more credence to this answer).
'replies' with its final letter removed is 'replie'.
'replie' placed around 'cat' is 'REPLICATE'.
Can you help me to learn more?
(Other definitions for replicate that I've seen before include "Copy exactly" , "Copy, reproduce" , "Make an exact copy of" .)