Crazy cat starts shedding and behaves (4)
I believe the answer is:
acts
'behaves' is the definition.
('act' can be a synonym of 'behave')
'crazy cat starts shedding' is the wordplay.
'crazy' is an anagram indicator.
'starts' indicates taking the first letters.
The first letter of 'shedding' is 's'.
'cat' is an anagram of 'act'.
'act'+'s'='ACTS'
'and' acts as a link.
(Other definitions for acts that I've seen before include "Performances" , "Performs on stage" , "Behaves or plays" , "Pretends" , "New Testament book immediately following the Gospels" .)