Score five fours (6)
I believe the answer is:
twenty
'score' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for twenty that I've seen before include "No longer a teenager" , "No. between 5 and 1 on dartboard" , "Dozen plus eight" , "with two crosses" , "Figure" .)