To indicate with one's body language for someone to move to one side, especially to be out of the way or earshot of others. A noun or pronoun can be used either before or after "aside." The driver of the car flashed his badge to the security guard and motioned him aside. The principal motioned aside the teacher so she could speak to him in private.
motion someone aside
to give a hand signal to someone to move aside. (See also motion someone to one side.) He motioned her aside and had a word with her. I motioned aside the guard and asked him a question.