Put on (a show) (5)
(Other definitions for stage that I've seen before include "Support for acting" , "Elevated platform" , "Acting platform; coach" , "Present; part of journey" , "division" .)
'put on a show' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for act that I've seen before include "Routine" , "Perform theatrically" , "Do something (on stage?)" , "work" , "Parliamentary decree" .)