Signs of sorrow when rebel interrupts masters? (8)
I believe the answer is:
teachers
'masters?' is the definition.
(as in schoolmasters)
'signs of sorrow when rebel interrupts' is the wordplay.
'signs of sorrow' becomes 'tears' (tears cried in sorrow).
'when rebel' becomes 'che' (I can't justify this - if you can you should give a lot more credence to this answer).
'interrupts' indicates putting letters inside.
'tears' placed around 'che' is 'TEACHERS'.
(Other definitions for teachers that I've seen before include "They impart knowledge" , "Pedagogues" , "Coaches" , "Instuctors" , "Instructors" .)