Cords (5)
I believe the answer is:
ropes
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cords</span>' is the definition.<br/ ><span class="explanation-format__explanation">(rope is a kind of cord)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ropes that I've seen before include "known to be adept?" , "lines" , "They're known by experts" , "weaker people may be on them?" , "known by clued-up workers?" .)