A hooker at sea, perhaps (6)
I believe the answer is:
angler
'a hooker' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for angler that I've seen before include "Sportsman" , "One proverbially exaggerating" , "I may do casting" , "One hoping for a catch" , "Walton's was Compleat" .)