Slope of a nose (6)
I believe the answer is:
ascent
'slope' is the definition.
(I know that ascent is a type of slope)
'a nose' is the wordplay.
'nose' becomes 'scent' (synonyms).
'a'+'scent'='ASCENT'
'of' acts as a link.
(Other definitions for ascent that I've seen before include "A climb or way up" , "way up the mountain" , "The climbing of a peak" , "Upwards motion" , "(A) climb (up mountain)" .)