Pristine cold slope (5)
I believe the answer is:
clean
'pristine' is the definition.
(similar in meaning)
'cold slope' is the wordplay.
'cold' becomes 'C' (eg on taps).
'slope' becomes 'lean' (I've seen this in another clue).
'c'+'lean'='CLEAN'
(Other definitions for clean that I've seen before include "Remove dirt or stain" , "Spick and span" , "Squeakily hygienic?" , "Absolute - pure" , "Uncontaminated" .)