Retract net opinion that's differing (6)
I believe the answer is:
unlike
I believe this is a double definition.
'retract net opinion' is the first definition.
(retract a 'like' on social media)
'differing' is the second definition.
(thesaurus)
'that's' acts as a link.
(Other definitions for unlike that I've seen before include "Not similar or comparable to" , "Dissimilar" , "Different from" .)