Votes cast about embargo, initially (6)
I believe the answer is:
vetoes
'votes' is the definition.
(I know this)
'cast about embargo initially' is the wordplay.
'cast about' becomes 'es' (I can't explain this - if you can you should believe this answer much more).
'embargo' becomes 'veto' (I've seen this before).
'initially' says to put letters next to each other.
'es' after 'veto' is 'VETOES'.
(Other definitions for vetoes that I've seen before include "Votes to block a decision" , "Casts over-riding negative vote" , "E votes to block decisions" , "Refuses to allow" .)