mutism

[ myoo-tiz-uh m ]

/ ˈmyu tɪz əm /

an inability to speak, due to a physical defect, conscious refusal, or psychogenic inhibition.

Origin of mutism

From the New Latin word mūtismus, dating back to 1815–25. See mute, -ism

It is not unlike the ordinary stupor in the fact that there was intense inactivity and mutism with great tenseness.

Benign Stupors |August Hoch
Dumb walls merely, their mutism leaves large scope to imagination, and one may conjecture any but the right thing.

The Mayas, the Sources of Their History / Dr. Le Plongeon in Yucatan, His Account of Discoveries |Stephen Salisbury, Jr.
From the description this again seems to have been a typical stupor (immobility, mutism, tendency to catalepsy, rigidity).

Benign Stupors |August Hoch
Her mutism and refusal of food she was unable to account for.

Benign Stupors |August Hoch

Later, this was followed by mutism, refusal to eat, and stupor.

Studies in Forensic Psychiatry |Bernard Glueck

mutism

/ (ˈmjuːtɪzəm) /

the state of being mute

psychiatry

mutism

[ myōō′tĭz′əm ]

Absence of the faculty of speech.