About five in container come out on top (7)
I believe the answer is:
prevail
'come out on top' is the definition.
(I've seen this in another clue)
'about five in container' is the wordplay.
'about five' becomes 'rev' (I can't justify this - if you can you should believe this answer much more).
'in' indicates putting letters inside.
'container' becomes 'pail' (pail is a kind of container).
'rev' going into 'pail' is 'PREVAIL'.
Can you help me to learn more?
(Other definitions for prevail that I've seen before include "Gain mastery" , "Be victorious" , "Be widespread; prove superior" , "Successfully persuade" , "Get one's way" .)