How to use a Wordpress function on an external website?

i want to use a shortcode or a function of a plugin on an external website. Is it possible?

Examples:

Shortcode: [super-post id="5"]

Function: <?php super_post_shortcode(5); ?>

That plugin shows posts-previews of my blog and i want to show them on a sidebar on another non-wordpress site.

via Chebli Mohamed