He thought for a brief space; then his jaw set.

The set of his jaw was something Cohen hadn't seen before.

But I knew him, and the stiff set of his jaw.

He stood and looked at her for a moment, hands on hips, jaw set.

But resolution showed in the set of her jaw, and that was good.

The grim set of the human's jaw told her he wasn't happy with what he'd seen.

He could see it in the rather stubborn set of her jaw.

The set of his jaw made it obvious he could be drawn no further.

Jane stared after them with her jaw set, then turned on Tom.

He glared at her, jaw set, as she smiled and walked out the door.