Anarchy in port the conclusion of Brexit? (4)
I believe the answer is:
riot
'anarchy' is the definition.
(thesaurus)
'port the conclusion of brexit?' is the wordplay.
'port' becomes 'rio' (I've seen this before).
'the conclusion of' indicates one should take the final letters.
The final letter of 'brexit' is 't'.
'rio'+'t'='RIOT'
'in' acts as a link.
(Other definitions for riot that I've seen before include "Crowd violence" , "Uprising" , "Wild disturbance by crowd of people" , "Take to the streets" , "Civil unrest" .)