Feline let out some cows (6)
I believe the answer is:
cattle
'some cows' is the definition.
('cattle' can be a synonym of 'cows')
'feline let out' is the wordplay.
'feline' becomes 'cat' (I've seen this before).
'out' is an anagram indicator (out can mean wrong or inaccurate).
'let' is an anagram of 'tle'.
'cat'+'tle'='CATTLE'
(Other definitions for cattle that I've seen before include "Livestock, kine" , "Cows, steers" , "Animals raised for meat" , "Farm animals" , "Oxen, cows, bulls etc" .)