Strong Negativity:
* Stubborn: This is the most direct synonym, emphasizing the refusal to change one's mind.
* Obstinate: Similar to stubborn, but with a stronger implication of being unreasonable and unyielding.
* Headstrong: Suggests a strong will that is difficult to control or redirect.
* Intransigent: Implies complete unwillingness to compromise or change position.
* Unyielding: Emphasizes the firmness and inflexibility of the person.
* Uncompromising: Similar to intransigent, suggesting a refusal to negotiate or make concessions.
* Bullheaded: A more colloquial term, suggesting a lack of reason and a tendency to be forceful.
* Pigheaded: Similar to bullheaded, but with a stronger sense of foolishness and obstinacy.
More Neutral:
* Determined: Suggests strong resolve and commitment to a particular course of action.
* Persistent: Emphasizes the continuation of an effort despite obstacles.
* Tenacious: Similar to persistent, but with a stronger sense of holding onto something.
* Resolute: Implies firmness and unwavering commitment.
Other Related Words:
* Dogged: Suggests a relentless and unwavering approach.
* Unbending: Implies a lack of flexibility and willingness to adapt.
* Inflexible: Similar to unbending, emphasizing the rigidity of the person's position.
* Unmovable: Indicates that the person is impossible to persuade or change.
The best synonym for "mulish" will depend on the specific context and the desired shade of meaning.