Reminder to include heathen article for indoctrination? (10)
I believe the answer is:
propaganda
'for indoctrination?' is the definition.
(I've seen this before)
'reminder to include heathen article' is the wordplay.
'reminder' becomes 'prod' (I've seen this before).
'to include' is an insertion indicator.
'heathen' becomes 'pagan' (both can mean an irreligious person).
'article' becomes 'a' (the indefinite article in English).
'prod' enclosing 'pagan' is 'propagand'.
'propagand'+'a'='PROPAGANDA'
(Other definitions for propaganda that I've seen before include "Hype" , "PR" , "publicity material" , "Dissemination of information" , "Politically biased information" .)