Joins or misguidedly unties (6)
I believe the answer is:
unites
'joins' is the definition.
('unite' can be a synonym of 'join')
'misguidedly unties' is the wordplay.
'misguidedly' is an anagram indicator.
'unties' with letters rearranged gives 'UNITES'.
'or' acts as a link.
(Other definitions for unites that I've seen before include "Becomes one" , "Joins or brings together" , "Joins together as one" , "Comes together for a common purpose" , "Confederates" .)