Hitch cables to rocks (8)
I believe the answer is:
obstacle
'hitch' is the definition.
(thesaurus)
'cables to rocks' is the wordplay.
'rocks' indicates an anagram.
'cables'+'to'='cablesto'
'cablesto' is an anagram of 'OBSTACLE'.
(Other definitions for obstacle that I've seen before include "The problem" , "Thing that obstructs progress" , "Barrier or deterrent" , "Anything that stands in the way" , "Maybe let" .)