Argue, or give in (6)
I believe the answer is:
submit
I believe this clue is a double definition.
'argue' is the first definition.
(thesaurus)
'give in' is the second definition.
('submit' can be a synonym of 'give in')
'or' is the link.
(Other definitions for submit that I've seen before include "Surrender or propose" , "Yield, surrender" , "Defer, give in" , "Surrender, or present for decision" , "Present (an application)" .)