not (Structured Query)

Inverts the matching of a query constructor so documents that don't match the query constructor are returned.

The following query will return documents where the author value is not equal to "Noam Chomsky":

{"not":
    {
        "key": "author"
        "equals": "Noam Chomsky"
    }
}

<not>
    <constraint>
        <key>author</key>
        <equals>Noam Chomsky</equals>
    </constraint>
</not>