I want to protect from copy and paste/right-clicking only the content of this custom field:
$cin = esc_html__(get_post_meta( $post->ID, 'cin_code', true), 'sacconicase');
Up to now I found solutions only for the entire site content, such as this java, to be put in js folder
document.addEventListener( 'contextmenu', function(e) {
e.preventDefault();
}, false);