The Baker Act is a law in Florida that allows mentally ill people to be committed to a mental health facility for 72 hours, against the will of the mentally ill person. It is commonly used as a verb. As far as I know, it is often used on people who are dangerous to themselves, for example, if they are hurting themselves intentionally, or on people who become violent and try to hurt others.
Here's what Wikipedia says:
Involuntary commitment under the Baker Act requires that a judge, police officer, or doctor find that a person is mentally ill enough to require an involuntary medical exam. Those persons deemed by court to be a danger to themselves and others around them may be involuntarily committed.
Within 72 hours of examination, the person may be released or may consent to further inpatient treatment. If not, the facility that conducted the exam must file an involuntary commitment petition that must be heard by a court within five days.
I knew a girl who got Baker Acted after she wouldn't stop cutting herself.