King meeting unruly body of soldiers (8)
I believe the answer is:
regiment
'body of soldiers' is the definition.
'king meeting unruly' is the wordplay.
'king' becomes 'r' (r is abbreviation for rex).
'unruly' is an anagram indicator.
'meeting' with letters rearranged gives 'egiment'.
'r'+'egiment'='REGIMENT'
(Other definitions for regiment that I've seen before include "Order" , "Large army unit" , "a whole lot of them" , "Brigade" , "Military group" .)