Proverb from Armada gentlemen (5)
I believe the answer is:
adage
'proverb' is the definition.
(synonyms)
'from armada gentlemen' is the wordplay.
'from' says the answer is hidden in the clue.
'ADAGE' is hidden within 'armada gentlemen'.
(Other definitions for adage that I've seen before include "True proverb or saying" , "Slogan" , "Old saw" , "say it again and again!" , "Proverb expressing a general truth" .)