1. To familiarize oneself thoroughly with.
2. To get involved in or with; SYN. tangle with.
3. When you get in or get into a place, building, room, car, boat, and so on, you enter it.

1. When you get something in or get something into a place, building, room, container, enclosure, and so on, you get the object inside even though it is difficult.
2. When you get in trouble or get into a difficult situation or a mess (a mess is a confused or difficult situation), you become involved in it. When you get people in trouble or get them into a difficult situation or a mess, you cause them to become involved in it.