stick in the mud
[noun]
Synonyms: fogy, antediluvian, fogram, fossil, fuddy-duddy, mid-Victorian, moldy fig, mossback, square

[TahlilGaran] English Synonym Dictionary ▲

ˈstick-in-the-ˌmud noun [countable]
someone who refuses to try anything new – used to show disapproval

[TahlilGaran] Dictionary of Contemporary English ▲

stick-in-the-mud
someone who has old-fashioned ideas and does not want to try new activities.
'Anyway, I'm not interested in married men.' 'Oh, don't be such a stick-in-the-mud.'

[TahlilGaran] English Idioms Dictionary ▲

stick in the mud
n., informal An overcareful person; someone who is old-fashioned and fights change.
Mabel said her mother was a real stick-in-the-mud to make a rule that she must be home by 10 o'clock on weeknights and 11:30 Saturdays.
Mr. Thomas is a stick-in-the-mud who plows with mules; he won't buy a tractor.

[TahlilGaran] English Idioms Dictionary ▲