A mere feline, one might imagine, but it's a mongoose (7)
I believe the answer is:
meerkat
'mongoose' is the definition.
(I've seen this before)
'a mere feline one might imagine but it's a' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
an anagram of 'mere' is 'meer' which is within the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
A single letter 'k' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for meerkat that I've seen before include "S. African animal" , "Strange tee mark made by the four-toed animal" , "Wild animal" , "Small southern African mammal" , "Small southern African mongoose" .)