Green’s Dictionary of Slang

a fussy, pernickety, narrow-minded person, often with the assumption of their being old.

1874		New Gloucester Centennial 7 Sept. 114: He went by the not very classical name of old ‘Fuddyduddy’.
1886		E.A. Allen Triangular Society 146: The Parson was an old fuddy-duddy who died before I was born.
1907		Carr & Chase ‘Word-List From Eastern Maine’ in DN III:iii 244: fuddy-duddy, n. and adj. A fussy man; a mature man who lacks masculinity. ‘He’s an awful old fuddy-duddy.’.
1914		G.A. England ‘Rural Locutions of Maine and Northern New Hampshire’ in DN IV:ii 72: fuddydud, or fuddyduddy, n. Fussy person.
1938		D. Moffat Mott Family in France 191: Mr. Mott wandered along [...] looking eternally at the damned view of the Promenade and the damned old fuddy-duddies who cluttered it up.
1940		Topeka Capital 12 Apr. 8a: These well-meaning intellectual fuddie-duddies [members of Peace Pledge Union in wartime England] have no remote conception of what is in store.
1951		Kerouac On the Road (The Orig. Scroll) (2007) 260: I decided not to be a fuddy and did likewise [i.e. stripped naked].
1956		‘Charles Raven’ Und. Nights 200: It was part of his graft to look, dress, and act like a benevolent old fuddy-duddy.
1958		Murtagh & Harris Cast the First Stone 165: I was brought up in the old school that says a woman’s got to please her man. But my wife [...] calls me a fuddy-dud.
1958		Southern & Hoffenberg Candy (1970) 103: I’m still on Eliot — the darling old fuddy, don’t you love him? [Ibid.] 153: Your fuddy-duddy old daddykins is missing in action.
1964		L. Nkosi Rhythm of Violence II ii: Some priests can be pretty militant. A damn sight more militant than some of the fuddy-duddies who pass as politicians!
1978		A. Maupin Tales of the City (1984) 192: We’re not a couple of old fuddy-duddies.
1980		M. Thelwell Harder They Come 246: The old fuddy-duddies exploded.
1983		‘Heat Moon’ Blue Highways 107: Even grumpy fuddy-dud like it.
1990		R. Campbell Sweet La-La Land (1999) 162: What would an old fuddy-duddy like me know about the fashions of young women?
2007		Morn. Call (Allentown, PA) 31 July 4/1: It was difficult to find passages in Ludacris’ lyrics that the fuddy-duddies [...] would let me repeat.
2012		News Messenger (Fremont, OH) 5 May 7/1: When it comes to technology I’m what we used to call an old fiddy-duddy.