to join; to connect; to link up; to communicate

to go through; to know well; (suffix) expert; to connect; to communicate; open; to clear; classifier for letters, telegrams, phone calls etc

classifier for an activity, taken in its entirety (tirade of abuse, stint of music playing, bout of drinking etc)

to be connected; traffic; transportation; communications; liaison

to be obstructed; to be blocked up; to be impassable; to make no sense; to be illogical