Persistent criminal's hit facing time (8)
I believe the answer is:
constant
'persistent' is the definition.
(thesaurus)
'criminal's hit facing time' is the wordplay.
'criminal's' becomes 'con's' (abbreviation for 'convict').
'hit' becomes 'tan' (tan can mean to beat or hit).
'facing' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'cons'+'tan'+'t'='CONSTANT'
(Other definitions for constant that I've seen before include "Faithful - unchanging" , "Recurring and unchanging" , "sustained" , "without changes" , "Stable" .)