All 5 Uses

impassive
in
The Memory Keeper’s Daughter
(Auto-generated)

Still, Caroline watched the faces in front of her turn impassive, masked.†
p. 161.7
She remembered the scents of boiled vegetables, and the day she had driven away with Phoebe, and the impassive expressions worn by the men on the board of education.†
p. 169.1 *
She raised her hand to slap the bland, impassive face of the nurse, but Al caught her wrist.†
p. 169.1
He glanced away, and when he looked back his father's expression was distant again, impassive.†
p. 215.6
Beyond, the revolving door turned and turned, flashing light and dark, spilling strangers inside or out, one by one, and then it was David striding across the terrazzo floor, his black shoes squeaking, his expression serious and impassive, impossible to read.†
p. 300.3

Definitions:

(1) (impassive)
having or revealing little emotion -- especially under circumstances others would find exciting
(2) (meaning too rare to warrant focus)