It's edgy where there's a chance of falling overboard (7)
I believe the answer is:
gunwale
'where there's a chance of falling overboard' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for gunwale that I've seen before include "Upper edge of ship's side" , "part of boat" , "Topmost planking of a wooden vessel" , "board" , "Part of craft" .)