concussion

con·cus·sion

noun \kən-ˈkəsh-ən\

Definition of CONCUSSION

1

: a hard blow or collision

2

: a condition resulting from the stunning, damaging, or shattering effects of a hard blow; especially : a jarring injury of the brain resulting in disturbance of cerebral function and sometimes marked by permanent damage

—con·cus·sive \-ˈkəs-iv\ adjective