Joint ideally clipped, rolled (6)
I believe the answer is:
allied
'joint' is the definition.
(I've seen this in another clue)
'ideally clipped rolled' is the wordplay.
'clipped' means to remove the last letter.
'rolled' indicates anagramming the letters.
'ideally' with its last letter taken off is 'ideall'.
'ideall' anagrammed gives 'ALLIED'.
(Other definitions for allied that I've seen before include "Joined by, eg, treaty" , "Joined together for a purpose" , "In league" , "Joined by treaty or agreement" , "Joined in friendship, treaty, etc" .)