Fear Republican stopping late (5)
I believe the answer is:
dread
'fear' is the definition.
(synonyms)
'republican stopping late' is the wordplay.
'republican' becomes 'R' (abbreviation).
'stopping' indicates putting letters inside (stopping can mean blocking a gap).
'late' becomes 'dead' (similar in meaning).
'r' put within 'dead' is 'DREAD'.
(Other definitions for dread that I've seen before include "Great fear or apprehension" , "Apprehensive fear" , "Hairstyle" , "Get cold feet" , "quail" .)