Cat returns in funny hat and tie (6)
I believe the answer is:
attach
'tie' is the definition.
(to tie is to link or attach)
'cat returns in funny hat' is the wordplay.
'returns' shows that the letters should be reversed in order.
'in' indicates putting letters inside.
'funny' indicates an anagram.
'cat' back-to-front is 'tac'.
'hat' with letters rearranged gives 'ath'.
'tac' put into 'ath' is 'ATTACH'.
'and' is the link.
(Other definitions for attach that I've seen before include "Add on to, couple" , "Join to something else" , "Tie, bind to" , "Fasten - attribute" , "Add or join to" .)