Mulish means stubbornly refusing to change your mind or do what others want, like a mule that plants its hooves and won't budge no matter how hard you pull. When someone acts mulish, they dig in and resist, often for no good reason beyond sheer determination not to cooperate.

You might see mulish behavior when a younger sibling refuses to clean their room despite repeated requests, or when a teammate won't consider anyone else's strategy for winning a game. The word suggests an unreasonable, obstinate refusal to listen or compromise, a stubbornness that goes beyond having good reasons for your position.

Mules earned their stubborn reputation through centuries of farm work. These sturdy animals, a cross between horses and donkeys, are actually quite intelligent. When a mule stops moving, it's often because it senses danger or is exhausted. But people use mulish to describe stubbornness that lacks that practical wisdom, the kind where someone refuses to budge simply because they've decided not to, regardless of whether their position makes sense.