Stick in the mud

The phrase "Stick in the mud" is an idiomatic expression that refers to a person who is considered excessively conservative, resistant to change, or lacks a sense of adventure or spontaneity. It describes someone who is unwilling to participate in or enjoy new or fun experiences, preferring to stick to traditional or familiar ways of doing things. The term is often used to criticize or mock individuals who resist innovation or exhibit a dull or rigid personality.