Talk foolishly about current danger on the seas (6)
I believe the answer is:
pirate
'danger on the seas' is the definition.
(pirates are a danger at sea)
'talk foolishly about current' is the wordplay.
'talk foolishly' becomes 'prate' (to prate is to talk nonsense).
'about' is an insertion indicator.
'current' becomes 'I' (symbol for electric current).
'prate' going around 'i' is 'PIRATE'.
(Other definitions for pirate that I've seen before include "fake" , "Use (another's work) for profit without permission" , "Rat pie (anag)" , "plagiarist" , "Penzance marauder ?" .)