Historic instrument? It sounds dreadful (4)
I believe the answer is:
viol
'historic instrument? it' is the definition.
I can't judge whether this definition defines the answer.
'sounds dreadful' is the wordplay.
'sounds' indicates a 'sounds like' (homophone) clue.
'dreadful' becomes 'vile' (I've seen this in another clue).
'vile' sounds like 'VIOL'.
Can you help me to learn more?
(Other definitions for viol that I've seen before include "Early fiddle" , "Double bass relative" , "Old six-stringed instrument played with a bow" , "Old consort instrument" , "Old string instrument" .)