It means "to do, to act, to drive, to lead, to conduct, to perform." This root appears in many English words related to action, such as:
* Agent: someone who acts or performs a particular function.
* Agile: able to move quickly and easily.
* Act: a deed, performance, or behavior.
* Active: engaged in action or performing a function.
* Agenda: a list of things to be done or considered.
* Coagulate: to thicken or congeal, often referring to blood.
And many more!