Twice (6)
I believe the answer is:
double
'twice' is the definition.
(synonyms)
This is all the clue.
(Other definitions for double that I've seen before include "Offence of leaving one's car where it blocks another" , "Ringer - large drink" , "Twice the amount" , "Twice - bent over - run" , "- - -u, (w)" .)