Precious peace Liberal shattered embracing Republican (13)
I believe the answer is:
irreplaceable
'precious' is the definition.
(thesaurus)
'peace liberal shattered embracing republican' is the wordplay.
'shattered' indicates anagramming the letters.
'embracing' means one lot of letters goes inside another.
'republican' becomes 'r' (abbreviation).
'peace'+'liberal'='peaceliberal'
'peaceliberal' is an anagram of 'ireplaceable'.
'ireplaceable' placed around 'r' is 'IRREPLACEABLE'.
(Other definitions for irreplaceable that I've seen before include "Unique" , "Cannot be substituted" , "Impossible to substitute for" , "precious!" , "Without possible substitute" .)