Effective narration (7)
I believe the answer is:
telling
I believe this is a double definition.
'effective' is the first definition.
(synonyms)
'narration' is the second definition.
(I know that telling is a type of narration)
(Other definitions for telling that I've seen before include "Powerful; relating" , "Striking, having noticeable effect" , "Effective - narration" , "relation" , "of significance" .)