Sailor carefully nets whale (4)
I believe the answer is:
orca
'whale' is the definition.
(orca is a kind of whale)
'sailor carefully nets' is the wordplay.
'ORCA' is hidden in amongst the letters.
However, I am not sure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for orca that I've seen before include "Killer whales" , "grampus" , "Large mammal" , "ship" , "Killer in deep" .)