Rope seaman primarily leaves alone (7)
I believe the answer is:
strands
'leaves alone' is the definition.
'rope seaman primarily' is the wordplay.
'rope' becomes 'strand'.
'primarily' suggests taking the first letters.
The first letter of 'seaman' is 's'.
'strand'+'s'='STRANDS'
(Other definitions for strands that I've seen before include "Threads or beaches" , "Filaments" , "Strings or chains" , "Leaves helpless on the sand" , "Threads, fibres" .)