In theory working daily (2,5)
I believe the answer is:
on paper
'in theory' is the definition.
(synonyms)
'working daily' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'daily' becomes 'paper' (newspaper).
'on'+'paper'='ON PAPER'
(Other definitions for on paper that I've seen before include "Propane (anag.)" , "Planned (in theory)" , "Hypothetically" , "Exam may be" , "Theoretically" .)