In each frame, Ai faces the camera, impassive and nearly immobile.
The high schoolers in the room are impassive, but the fathers give thoughtful frown-nods.
1660s, "not feeling pain," from assimilated form of in- "not, opposite of" (see in- (1)) + passive. Meaning "void of emotions" is from 1690s. Related: Impassively; impassiveness (1640s).