Demote oldest pastor, essentially for being shy (6)
I believe the answer is:
modest
'being shy' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for modest that I've seen before include "Mussorgsky, nominally?" , "Prudent" , "'Unassuming, diffident (6)'" , "Bashful" , "Having a humble opinion of oneself" .)