Sailor comes up a rope - this one? (7)
I believe the answer is:
ratline
'one?' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'sailor comes up a rope' is the wordplay.
'sailor' becomes 'tar' (slang term for a sailor).
'comes up' says the letters should be written backwards (in a down clue, letters go up).
'a rope' becomes 'line' (I've seen this in other clues).
'tar' written backwards gives 'rat'.
'rat'+'line'='RATLINE'
'this' acts as a link.
Can you help me to learn more?
(Other definitions for ratline that I've seen before include "Reliant (anag.)" , "Rope forming part of steps on ship's rigging" , "Small rope for climbing on rigging" .)