fuddy-duddy
Concise Oxford English Dictionary © 2008 Oxford University Press:
fuddy-duddy/ˈfʌdidʌdi/
▶noun (pl. fuddy-duddies) informal a person who is very old-fashioned and pompous.
– origin early 20th cent. (orig. dial.): of unknown origin.
'fuddy-duddy' also found in these Oxford entries:

