Criticised houses neglected at first on a slope (7)
I believe the answer is:
slanted
'on a slope' is the definition.
'criticised houses neglected at first' is the wordplay.
'criticised' becomes 'slated' (I've seen this in other clues).
'houses' indicates putting letters inside.
'at first' indicates taking the first letters.
The first letter of 'neglected' is 'n'.
'slated' enclosing 'n' is 'SLANTED'.
(Other definitions for slanted that I've seen before include "Sloped or biased" , "Leaning; biased" , "Partisan" , "At an angle" , "Sloping, leaning" .)