Embargo faced by old port (4)
I believe the answer is:
oban
'port' is the definition.
(I've seen this before)
'embargo faced by old' is the wordplay.
'embargo' becomes 'ban' (I've seen this before).
'faced by' means one lot of letters go next to another.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'ban' after 'o' is 'OBAN'.
(Other definitions for oban that I've seen before include "Argyll seaport" , "Scottish town" , "Scottish west coast resort" , "port required" , "Port in western Scotland" .)