Sermon in chapterhouse, disrupted when author leaves (6)
I believe the answer is:
speech
'sermon' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for speech that I've seen before include "Oration or talk" , "Oration, address" , "Formal spoken communication delivered to an audience" , "Talk given to an audience" , "Harangue" .)