Hurdle (8)

'hurdle' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for obstacle that I've seen before include "Thing that obstructs progress" , "The problem" , "It obstructs or hinders" , "Block to progress" , "Thing blocking progress" .)
'hurdle' is the definition.
(thesaurus)
This is the entire clue.