Tom-Tom the mimic? (7)
I believe the answer is:
copycat
'the mimic?' is the definition.
(I've seen this before)
'tom-tom' is the wordplay.
'tom' becomes 'copy' (I can't explain this - if you can you should believe this answer much more).
'tom' becomes 'cat' (I have seen 'A tom ' mean 'cat' so perhaps 'tom' could also mean 'cat').
'copy'+'cat'='COPYCAT'
Can you help me to learn more?
(Other definitions for copycat that I've seen before include "Person imitating another (or cloned pet?)" , "Mimic" , "Person (or crime) imitating another" , "not the original one" , "Person who imitates another in feline way" .)