One who respects Sunday (8)
I believe the answer is:
observer
This clue is a double definition.
'one who respects' is the first definition.
(eg one respecting or observing rules)
'sunday' is the second definition.
(Sunday newspaper)
(Other definitions for observer that I've seen before include "organ on Sunday" , "monitor" , "One watching attentively" , "I notice" , "Newspaper - witness" .)