Bored teen isn't rude, surprisingly (12)
I believe the answer is:
uninterested
'bored' is the definition.
('uninterested' can be similar in meaning to 'bored')
'teen isn't rude surprisingly' is the wordplay.
'surprisingly' is an anagram indicator.
'teen'+'isnt'+'rude'='teenisntrude'
'teenisntrude' is an anagram of 'UNINTERESTED'.
(Other definitions for uninterested that I've seen before include "Bored" , "Apathetic" , "indifferent" , "Not concerned" .)