Twerp at riot is maybe displaying 'national pride' (10)
I believe the answer is:
patriotism
'national pride' is the definition.
(I've seen this before)
'twerp at riot is maybe displaying' is the wordplay.
'displaying' says the answer is hidden in the clue.
'PATRIOTISM' is hidden within 'twerp at riot is maybe'.
(Other definitions for patriotism that I've seen before include "dedication to the country" , "Love of country" , "Strong support for one's country" , "support for state" , "loyalty" .)