To amicably accept opposing opinions (5,2,6)
I believe the answer is:
agree to differ
'to amicably' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'accept opposing opinions' is the wordplay.
'accept' becomes 'agree to' (I've seen this before).
'opposing opinions' becomes 'differ' (I am not sure about this - if you are sure you should believe this answer much more).
'agreeto'+'differ'='AGREE TO DIFFER'
Can you help me to learn more?
(Other definitions for agree to differ that I've seen before include "Coexist with opposing views" , "End argument amicably while maintaining different opinions" , "Fail to convince each other" , "Accept multiple opinions" , "Fail to meet" .)