Rhubarb found in beet, upside-down, back-to-front (7)
I believe the answer is:
dispute
'rhubarb' is the definition.
(thesaurus)
'in beet upside-down back-to-front' is the wordplay.
'in' indicates a hidden word.
'back-to-front' is a reversal indicator.
'etupsid' can be found hidden inside 'beet upside down'.
'etupsid' in reverse letter order is 'DISPUTE'.
'found' acts as a link.
(Other definitions for dispute that I've seen before include "conflict" , "Row" , "Question or deny accuracy or validity" , "Altercate" , "Quarrel over rights" .)