Sensational Republican fiddle covered up by Washington (8)
I believe the answer is:
dramatic
'sensational' is the definition.
(I've seen this in another clue)
'republican fiddle covered up by washington' is the wordplay.
'republican' becomes 'r' (abbreviation).
'fiddle' becomes 'amati' (violin created by the Amati family).
'covered up by' indicates putting letters inside.
'washington' becomes 'dc' (Washington DC).
'r'+'amati'='ramati'
'ramati' placed inside 'dc' is 'DRAMATIC'.
(Other definitions for dramatic that I've seen before include "Sensational, theatrical" , "Histrionic" , "Like theatre" , "Thrilling in effect" , "Sudden and striking" .)