Unruly mob are heading for Geoffrey Boycott (7)
I believe the answer is:
embargo
'boycott' is the definition.
(I've seen this before)
'unruly mob are heading for geoffrey' is the wordplay.
'unruly' indicates anagramming the letters.
'heading for' says to take the initial letters.
The first letter of 'geoffrey' is 'g'.
'mob'+'are'+'g'='mobareg'
'mobareg' anagrammed gives 'EMBARGO'.
(Other definitions for embargo that I've seen before include "Proscribe, ban" , "Admiralty order" , "Trade sanction" , "Ban, veto" , "Legal stoppage of commerce" .)