We are its cast, so to speak (2,2,4)
I believe the answer is:
as it were
'so to speak' is the definition.
('as it were' can be a synonym of 'so to speak')
'we are its cast' is the wordplay.
'cast' is an anagram indicator.
'we'+'are'+'its'='weareits'
'weareits' anagrammed gives 'AS IT WERE'.
(Other definitions for as it were that I've seen before include "you may say" , "As if it was actually so" , "Historically ungrammatical" , "In sort of" , "you might say" .)