Rock climber's challenge
I believe the answer is:
cliff
'rock climber's challenge' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for cliff that I've seen before include "Precipice" , "High, steep rock face" , "A sheer rock face, in mountain or by sea" , "stony face?" , "Steep high rockface" .)