trismus
Concise Oxford English Dictionary © 2008 Oxford University Press:
trismus /ˈtrɪzməs/
▶noun Medicine spasm of the jaw muscles, causing the mouth to remain tightly closed, typically as a symptom of tetanus; lockjaw.
– origin C17: from mod. L., from Gk trismos ‘a scream, grinding’.
'trismus' also found in these Oxford entries:

