Lock up and Put behind bars

Lock up verb - To put in or as if in prison.

Put behind bars and lock up are semantically related in confine topic. In some cases you can use "Put behind bars" instead a verb "Lock up", when it comes to topics like incarcerate.

Put behind bars verb - Lock up or confine, in or as in a jail.

Lock up and put behind bars are semantically related in confine topic. You can use "Lock up" instead a verb phrase "Put behind bars", if it concerns topics such as incarcerate.