Holiness surprisingly intact in the outskirts of Surrey (8)
I believe the answer is:
sanctity
'holiness' is the definition.
('sanctity' can be a synonym of 'holiness')
'surprisingly intact in the outskirts of surrey' is the wordplay.
'surprisingly' indicates an anagram.
'in the' is an insertion indicator.
'outskirts of' says to hollow out the word (remove centre letters).
'surrey' with its middle removed is 'sy'.
'intact' anagrammed gives 'anctit'.
'anctit' inserted into 'sy' is 'SANCTITY'.
(Other definitions for sanctity that I've seen before include "Devotion" , "Condition of holiness" , "Tiny acts (anag) - godliness" , "Ultimate importance" , "Righteousness" .)