Functioned
'functioned' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for acted that I've seen before include "took part in simulation" , "Behaved or played a part" , "Worked" , "Performed on stage" , "Appeared in play" .)
'functioned' is the definition.
('operate' can be a synonym of 'function')
This is all the clue.
(Other definitions for operated that I've seen before include "Functioned" , "'Directed or controlled, machinery say (8)'" , "Performed surgery or worked a machine" , "ran" , "Adore pet (anag.)" .)