Picture buff doctor that is pursuing lover essentially promising proposal (9)

I believe the answer is:
moviegoer
'picture buff doctor that is pursuing lover essentially promising proposal' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'picture buff doctor that is pursuing' is the wordplay.
'picture' becomes 'movie' (synonyms).
'buff doctor' becomes 'goer' (I am not sure about this - if you are sure you should believe this answer much more).
'that is pursuing' is a charade indicator (letters next to each other).
'movie'+'goer'='MOVIEGOER'
Can you help me to learn more?
(Other definitions for moviegoer that I've seen before include "Who goes to the flicks" , "One out for pictures" , "one getting into shorts?" , "One attending films ( US )" .)
