Sound frightened following Republican stink (4)
I believe the answer is:
reek
'stink' is the definition.
(I know that reek is a type of stink)
'sound frightened following republican' is the wordplay.
I cannot quite see how this works, but
'sound' could be 'eek' (I have seen 'Sound of alarm' mean 'eek' so perhaps 'sound' could also mean 'eek') and 'eek' is present in the answer.
'republican' could be 'r' (abbreviation in US politics) and 'r' is present in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for reek that I've seen before include "bad odour" , "Fume" , "Pong" , "'Stink, stench (4)'" , "Smell to high heaven" .)