Clash involving Times grandee (12)
I believe the answer is:
disagreement
'clash' is the definition.
(thesaurus)
'involving times grandee' is the wordplay.
'involving' is an anagram indicator.
'times'+'grandee'='timesgrandee'
'timesgrandee' is an anagram of 'DISAGREEMENT'.
(Other definitions for disagreement that I've seen before include "Difference of opinion" , "Argument" , "Conflict" , "Contretemps" , "dispute" .)