British university expresses revolutionary argument (4-2)
I believe the answer is:
bust-up
'argument' is the definition.
(a bust-up is an argument or quarrel)
'british university expresses revolutionary' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'university' becomes 'U' (abbreviation for university).
'expresses' becomes 'puts' (I've seen this in another clue).
'revolutionary' says the letters should be written in reverse (letters revolve around).
'puts' backwards is 'stup'.
'b'+'u'+'stup'='BUST-UP'
(Other definitions for bust-up that I've seen before include "Quarrel, possibly ending a friendship" , "Serious quarrel/fight" , "Argument finishing a relationship" , "Serious quarrel or fight (B, not D)" , "Quarrel, brawl" .)