1.  to entrust (someone) with;  to leave (a matter) with someone;  to place under someone's care
2.  to have someone deliver (a message, parcel, etc.);  to send (through someone);  to leave (a message) with someone
3.  to use (something) to express (one's feelings, opinion, etc.);  to express in the form of (something)
4.  to use as a pretext