Way of saving face, so only come in disguise (7)
'way of saving' is the definition.
'economy' can be an answer for 'saving' ('economy' can be a synonym of 'saving'). I am not certain of the 'way of' bit.
I cannot understand how the rest of the clue works.
(Other definitions for economy that I've seen before include "Thrift - national production, distribution and consumption" , "Judicious expenditure of money" , "Country's system of wealth creation" , "Careful use of resources" , "Financial system" .)
'way of saving' is the definition.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Another definition for economy of scale that I've seen is " Sizeable savings".)