Cat English see in October (6)
I believe the answer is:
ocelot
'cat' is the definition.
(I know that ocelot is a type of wildcat)
'english see in october' is the wordplay.
'english' becomes 'e' (abbreviation).
'see' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'in' means one lot of letters goes inside another.
'october' becomes 'Oct' (synonyms).
'e'+'lo'='elo'
'elo' placed within 'oct' is 'OCELOT'.
(Other definitions for ocelot that I've seen before include "American wild cat" , "Striped and spotted wildcat" , "Feline mammal" , "Animal in the loo etc." , "South and Central American wildcat" .)