stick-in-the-mud

American  

[stik-in-thuh-muhd] / ˈstɪk ɪn ðəˌmʌd /

noun

1. someone who avoids new activities, ideas, or attitudes; old fogy.

---

stick-in-the-mud British  

noun

1. informal a staid or predictably conservative person who lacks initiative or imagination

---

Etymology

Origin of stick-in-the-mud

First recorded in 1725–35