A cat to make any fellow cross (4)
I believe the answer is:
manx
'a cat' is the definition.
(I know that Manx is a type of cat)
'any fellow cross' is the wordplay.
'any fellow' becomes 'man' (fellow can mean a man. I am not sure about the 'any' bit.).
'cross' becomes 'x' (an X is a cross).
'man'+'x'='MANX'
'to make' acts as a link.
Can you help me to learn more?
(Other definitions for manx that I've seen before include "Island's" , "Isle of Man's language" , "Adjective indicating the Isle of Man" , "Breed of tailless cat" , "Celtic language, relating to the Isle of Man" .)