what does "post a lookout"mean? His hand was dead steady (every eye was on it; now that he was President, his smallest gestures would be covertly observed by those around him), and although his own eyes were on the screen, he was issuing a spate of orders, reminding Rufus Youngblood to post a lookout for Jacqueline Kennedy, telling him to have the agents make a written record of their movements, and leading a running discussion with aides and Congressmen over the advisability of taking the Presidential oath immediately.