Northern plays were more original (5)
I believe the answer is:
newer
'more original' is the definition.
('new' can be similar in meaning to 'original')
'northern plays were' is the wordplay.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'plays' is an anagram indicator.
'were' anagrammed gives 'ewer'.
'n'+'ewer'='NEWER'
(Other definitions for newer that I've seen before include "Fresher or more novel" , "More up-to-date" , "More pristine or recently invented" , "More modern" , "More current" .)