Poet in turn welcomed by fat cat (7)
I believe the answer is:
leopard
'cat' is the definition.
(leopard is a kind of cat)
'poet in turn welcomed by fat' is the wordplay.
'poet' becomes 'poe' (Edgar Allan Poe).
'in turn' is a reversal indicator (letters turning around).
'welcomed by' is an insertion indicator (I've seen this in other clues).
'fat' becomes 'lard' (lard is a kind of fat).
'poe' reversed gives 'eop'.
'eop' put inside 'lard' is 'LEOPARD'.
(Other definitions for leopard that I've seen before include "Spotted big cat" , "Big cat with spots" , "dangerous when free" , "Large spotted cat" , "Spotted animal" .)