Hog's back; saddle (5)
I believe the answer is:
ridge
I believe this clue is a double definition.
'hog's back' is the first definition.
(I've seen this before)
'saddle' is the second definition.
(I've seen this before)
(Other definitions for ridge that I've seen before include "Line of higher ground" , "Narrow hill-range" , "German Baltic port, Buxtehude home" , "Peak" , "Long mountain crest or roof life" .)