Source from discourteous drawing room? (6)
I believe the answer is:
studio
'drawing room?' is the definition.
(room in which an artist might draw)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for studio that I've seen before include "Artist's workplace - where films are made" , "Where an artist works" , "Workroom of an artist or photographer" , "Here one may record" , "Artist's work room" .)