Neutral:
* Stern: This implies a serious and unsmiling expression.
* Grim: Suggests a dark and forbidding appearance.
* Hard-faced: Describes someone with strong, angular features that might be perceived as intimidating.
Negative:
* Scornful: This implies a look of contempt or disdain.
* Hostile: Suggests a threatening or aggressive demeanor.
* Menacing: This implies a sense of danger or threat.
* Vicious: A more extreme term suggesting cruelty and malice.
* Belligerent: Describes someone who is ready to fight or argue.
More nuanced:
* Aloof: This suggests someone who is distant and unapproachable, perhaps due to shyness or insecurity.
* Intimidating: This emphasizes the feeling of fear or unease the person inspires.
* Unfriendly: A general term for someone who doesn't seem welcoming or approachable.
The best word to use will depend on the specific situation and the impression you want to convey. Consider the person's actions and the context to choose the most accurate and appropriate term.