Penal reform is an Asian kingdom (5)
I believe the answer is:
nepal
'an asian kingdom' is the definition.
(I've seen this in another clue)
'penal reform' is the wordplay.
'reform' is an anagram indicator (letters in a new form).
'penal' with letters rearranged gives 'NEPAL'.
'is' is the link.
(Other definitions for nepal that I've seen before include "hilly part of Asia" , "mountainous area" , "Asian country, capital Kathmandu" , "Kathmandu's country" , "Small country high in the Himalayas" .)