Tend to slope (7)
I believe the answer is:
incline
This clue is a double definition.
'tend' is the first definition.
(synonyms)
'slope' is the second definition.
(I know that slope can be written as incline)
'to' is the link.
(Other definitions for incline that I've seen before include "Gradient" , "Bend forwards" , "List" , "Tend; lean" , "lean forward" .)