Command top vessel taking armada's lead (7)
I believe the answer is:
captain
'command' is the definition.
(thesaurus)
'top vessel taking armada's lead' is the wordplay.
'top' becomes 'cap' (both can mean to beat or outdo).
'vessel' becomes 'tin' (type of container).
'taking' indicates putting letters inside.
'armada's lead' becomes 'a' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tin' placed around 'a' is 'tain'.
'cap'+'tain'='CAPTAIN'
Can you help me to learn more?
(Other definitions for captain that I've seen before include "eg Hornblower" , "American police officer" , "Ship's commander" , "Skipper" , "Naval commander" .)