1.  to be open (to traffic);  to lead to;  to communicate (with)
2.  to flow (liquid, current);  to pass;  to get through to
3.  to be understood;  to be comprehended
4.  to be honored;  to be good
5.  to be well versed in;  to be well-informed
6.  to communicate clandestinely;  to keep in touch (e.g. with the enemy)
7.  to form a liaison;  to be intimate