Embargo on nobleman (5)
I believe the answer is:
baron
'nobleman' is the definition.
(baron is a kind of nobleman)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for baron that I've seen before include "British peer of the lowest rank" , "British peer; business mogul" , "Lowest title of peerage" , "Husband" , "Nobleman providing a portion of beef" .)