If someone holds your jaw aggressively and threatens you, is there a specific word to describe this action or situation?
Legal terms are not my strong point, but I think one might describe such an act as intimidation by using violence.
If someone holds your jaw aggressively and threatens you, the specific, legal designation for such action is Assault and Battery or "Intimidation and Battery."
Assault and Battery: Two separate offenses against the person that when used in one expression may be defined as any unlawful and unpermitted touching of another. Assault is an act that creates an apprehension in another of an imminent, harmful or offensive contact. The act consists of a threat of harm accompanied by an apparent, present ability to carry out the threat. Battery is a harmful or offensive touching of another.
The main distinction between the two offenses is the existence or nonexistence of a touching or a contact. While contact is an essential element of battery, there must be an absence of contact for assault. Sometimes assault is defined loosely to include battery.
It could be that they're intimidating you, or physically threatening you.
It could be that they are physically assaulting you, or physical intimidation. If wouldn't really be considered as battery because you weren't really being actually physically abused, just threatened. In legal terms, "assault" means physical intimidation and threat, while "battery" refers to the actual harm and abuse.