fuddy-duddy \FEH-dee-deh-dee\ (noun) - An old-fashioned, bland, rather prudish person, a softy who is easy to get along with, poses no threat but avoids anything exciting. Fuddy-duddies tend to be middle-aged or older; younger versions are "mama's boys" or "mama's girls."
"In the late afternoon the park is filled with fuddy-duddies out for the thrill of a casual stroll."
The origin of today's word is another mystery. It may be a reduplication of Scots fuddy or fuddie "animal tail, short-tailed animal" based on fud "buttocks, tail" + the suffix y. We just don't know. So where did "duddy" come from, you ask. Human beings love rhyme and rhythm, and those of the English persuasion have packed their language with nonsense compounds made up of trochaic rhymes (with accent on the first syllable), such as "itsy-bitsy," "willy-nilly," "hoity-toity," "jeepers-creepers" (euphemism for 'Jesus Christ'), "nitty-gritty," "roly-poly," "Humpty-Dumpty," "hanky-panky," "boogie-woogie," "razzle-dazzle," "pooper-scooper," "piggly-wiggly," "okey-dokey," and on and on and on. Why? Nonsense by definition cannot be explained.