set of one's jaw

Noun

 * 1)  The manner of one's lower facial expression, especially as suggesting firm resolve, or intensity of thought or feeling.
 * 2) * 1946,, The Road to Wimbledon, C. Scribner's Sons, p. 154 (Google snippet view):
 * But it was the set of her jaw and the coolness in her green eyes that made me feel how really formidable she was.
 * 1) * 1946,, The Road to Wimbledon, C. Scribner's Sons, p. 154 (Google snippet view):
 * But it was the set of her jaw and the coolness in her green eyes that made me feel how really formidable she was.