Twenty, the full total (5)
I believe the answer is:
score
This clue is a double definition.
'twenty' is the first definition.
('score' can be a synonym of 'twenty')
'the full total' is the second definition.
(Other definitions for score that I've seen before include "purchase of illegal drugs" , "Group of 20" , "Number of goals/points" , "Reckoning" , "Grade; twenty" .)