My grandma is a fuddy-duddy when it comes to keeping her house clean.
Origin of fuddy-duddy
American Heritage Dictionary of the English Language, 5th Edition
Unknown, c. 1900 US
Fuddy-duddy Sentence Examples
We know the world is changing and don't want to seem fuddy-duddy or to be left behind.
We're told it's going to replace fuddy-duddy old received pronunciation as the standard accent.
There's nothing more romantic than a long nightgown, but unfortunately many of them just don't have very modern sensibilities - in other words, they're too itchy or too fuddy-duddy to really be relevant with today's stylish woman.