Accept harsh version of slogan (5,6)
I believe the answer is:
catch phrase
'slogan' is the definition.
(thesaurus)
'accept harsh version' is the wordplay.
'version' indicates an anagram.
'accept'+'harsh'='acceptharsh'
'acceptharsh' is an anagram of 'CATCH-PHRASE'.
'of' is the link.
(Other definitions for catch phrase that I've seen before include "Familiar words (of comedian)" , "Oft repeated slogan" , "Well-known sentence" .)