Clash with a queen (3)
I believe the answer is:
war
'clash' is the definition.
(thesaurus)
'with a queen' is the wordplay.
'with' becomes 'w' (abbreviation).
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'w'+'a'+'r'='WAR'
(Other definitions for war that I've seen before include "State of armed conflict" , "Battle" , "Period of hostilities" , "Fight" , "Strife" .)