someone who is being watched by someone who wants to harm or kill them.
He is still free to travel the world, but he knows he is a marked man.
marked man
A person who is targeted for harm or retaliation of some kind. After Ed alerted the authorities about the corruption that took place within the company, he became a marked man.
a marked ˈman
a man who is in danger of being killed by his enemies: When they discovered he was a spy, he became a marked man.