City aware of being behind hill (7)
I believe the answer is:
toronto
'city' is the definition.
(Toronto is an example)
'aware of being behind hill' is the wordplay.
'aware of' becomes 'onto' (I've seen this before).
'being behind' says to put letters next to each other.
'hill' becomes 'tor' (tor is a kind of hill).
'onto' put after 'tor' is 'TORONTO'.
(Other definitions for toronto that I've seen before include "Provincial capital" , "Big city" , "Largest city in Canada" , "Canadian city" , "Canada's largest city" .)