Give up church and start doubling earnings (4)
I believe the answer is:
cede
'give up' is the definition.
('cede' can be a synonym of 'give up')
'church and start doubling earnings' is the wordplay.
'church' becomes 'ce' (abbreviation for Church of England).
'and' means one lot of letters go next to another.
'start' says to take the initial letters.
The initial letters of 'doubling earnings' is 'de'.
'ce'+'de'='CEDE'
(Other definitions for cede that I've seen before include "Yield or give up to another" , "Surrender or grant" , "Yield, give way" , "Relinquish control of" , "21 across" .)