What does "fuddy-duddy" mean?

An old-fashioned, persnickety or ineffective person.

What is a synonym for "fuddy-duddy"?

Common synonyms include: antediluvian, antique, back number, blimp, conservative, dad.

/ˈfʌdiˌdʌdi/ adj, noun, slang

adj, noun, slang ·Moderate ·College level

Noun

1
An old-fashioned, persnickety or ineffective person. US, informal
"My grandma is a fuddy-duddy when it comes to keeping her house clean."
2
a conservative who is old-fashioned or dull in attitude or appearance wordnet

Adjective

1
Old-fashioned and persnickety or ineffective. US, informal
"Kingsolver lives by the tenets of her public-spirited fictional characters, whom she sculpts with a keen eye for individuality, e.g. Nannie Land Rawley, a seventy-something orchardist who shocks a fuddy-duddy male neighbor by wearing shorts, […]"

"My uncle is a fuddy-duddy who thinks life was better back in the 1950s."

Unknown. First attested in the US circa 1900.