Spontaneously rejecting German newspaper article (2,3)
I believe the answer is:
ad lib
'spontaneously' is the definition.
(synonyms)
'rejecting german newspaper article' is the wordplay.
'rejecting' is a reversal indicator.
'german newspaper' becomes 'bild' (German daily newspaper).
'article' becomes 'a' (the indefinite article in English).
'bild'+'a'='bilda'
'bilda' back-to-front is 'AD-LIB'.
(Other definitions for ad lib that I've seen before include "Speak off the cuff, unrehearsed" , "Speak unprepared" , "Make an impromptu speech" , "Improvised" , "Speak unpreparedly" .)