Hitch cables to rock (8)
I believe the answer is:
obstacle
'hitch' is the definition.
(thesaurus)
'cables to rock' is the wordplay.
'rock' indicates an anagram.
'cables'+'to'='cablesto'
'cablesto' anagrammed gives 'OBSTACLE'.
(Other definitions for obstacle that I've seen before include "Hindrance, obstruction" , "It obstructs or hinders" , "Hurdle, impediment" , "Anything that stands in the way" , "stumbling block" .)