To ostracize is to deliberately exclude or leave someone out.
An example of ostracize is when you don't invite one person in the class to a party that everyone else is going to.
To exclude from a group or society.
To banish by ostracism, as in ancient Greece.
To banish, bar, exclude, etc.
Origin of ostracize
Greek ostrakizein from ostrakon shell, potsherd (from the potsherds used as ballots in voting for ostracism) ost- in Indo-European roots