Callous orders restricting most of the citizens, ultimately (8)
I believe the answer is:
ruthless
'callous' is the definition.
(thesaurus)
'orders restricting most of the citizens ultimately' is the wordplay.
'orders' becomes 'rules'.
'restricting' is an insertion indicator.
'most of' means to remove the last letter.
'ultimately' indicates one should take the final letters.
The final letter of 'citizens' is 's'.
'the' with its final letter removed is 'th'.
'rules' enclosing 'th' is 'ruthles'.
'ruthles'+'s'='RUTHLESS'
(Other definitions for ruthless that I've seen before include "Having no mercy like hustlers" , "nasty" , "Without pity, merciless" , "Unsparing" , "Lacking pity or mercy" .)