A more thorough explanation:

Definition: To outlaw or prohibit; to forbid. In Roman and civil law, to post or publish the name of a person as condemned to death and forfeiture of property.

1. The school has proscribed the use of cellphones during class hours.

2. In ancient Rome, those who committed treason were proscribed, and their property was seized by the state.

The first example shows how the term "proscribe" is used to mean "forbid." The school has prohibited the use of cellphones during class hours. The second example illustrates the historical use of the term in Roman law, where those who were condemned for treason were publicly named and their property was taken away.