Cliff? Treat man with respect (10)
I believe the answer is:
escarpment
'cliff?' is the definition.
(thesaurus)
'treat man with respect' is the wordplay.
'treat' is an anagram indicator.
'with' means one lot of letters go next to another.
'man' put after 'respect' is 'respectman'.
'respectman' anagrammed gives 'ESCARPMENT'.
(Other definitions for escarpment that I've seen before include "Face" , "Long edge of plateau" , "Steep slope - map's centre (anag)" , "Long steep slope at a plateau's edge" , "Steep slope at edge of plateau" .)