How to setup a honeypot with wp_mail to reduce spam

Hello,

I am using the following code in a modal. Lately we are receiving a lot of spam, how can I setup a honeypot ? What kind of custom field do i have to use ? I have placed some ??????? where I am stuck.

thank you very much for your help.

<?php
add_action( 'rwmb_frontend_after_process', function( $config, $post_id ) {
    if ( 'nachricht' !== $config['id'] ) {
        return;
    }

    $deine_email = rwmb_meta( 'deine_email', '', $post_id );
    $dein_name = rwmb_meta( 'dein_name', '', $post_id );
    $dein_betreff = rwmb_meta( 'dein_betreff', '', $post_id );
    $deine_nachricht = rwmb_meta( 'deine_nachricht', '', $post_id );
    $honeypot = ????? ;

    //the spam honey pot
    if ($honeypot != '') {
            ???????
    }

    $attachments = array();
    $to [] = $deine_email;
    $subject = "XXX";  
    $body = "<p><b>Name</b>: $dein_name</p>
        <p>Email: $deine_email</p>
        <p>Nachricht: $deine_nachricht</p><br><br>
        <p>bla bla bla</p>";
    $headers = array(
        'Content-type: text/html; charset=UTF-8',
        'Reply-To:' . $deine_email . '',
        'From: abc Marcus <[email protected]>',
        'BCC: $deine_email');

    wp_mail($to, $subject, $body, $headers, $attachments );
 
}, 10, 2 );
?>