Stop accepting Republican line (6)
I believe the answer is:
crease
'line' is the definition.
(synonyms)
'stop accepting republican' is the wordplay.
I cannot really understand how this works, but
'republican' could be 'r' (political abbreviation) and 'r' is located in the answer.
'stop' could be 'cease' (synonyms) and 'cease' is located in the remaining letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for crease that I've seen before include "Cricket line; wrinkle" , "Furrow; cricket line" , "ruck" , "Fold - wrinkle" , "Furrow, wrinkle" .)