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' indicates a hidden word.
'PATRIOTISM' can be found hidden inside '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" .)