Hospital above city accepting time for purity (8)
I believe the answer is:
sanctity
'purity' is the definition.
(thesaurus)
'hospital above city accepting time' is the wordplay.
'hospital' becomes 'san' (short for sanatorium).
'above' says to put letters next to each other (in a down clue, some letters go above others).
'accepting' indicates putting letters inside (inserted letters are accepted).
'time' becomes 't' (abbreviation).
'city' enclosing 't' is 'ctity'.
'san'+'ctity'='SANCTITY'
'for' acts as a link.
(Other definitions for sanctity that I've seen before include "Holiness, sacredness" , "that should concern church?" , "Untouchable quality" , "Great goodness" , "State of grace and holiness" .)