wp_enqueue_scripts

In a link element ids WP add -css, so you need to remove it.

May be this will help:

function remove_font_awesome() {
  wp_dequeue_style('geowidget-4.5-css'); // not geowidget-4.5-css-css
}
add_action ('wp_enqueue_scripts', 'remove_font_awesome', 9999);
add_action( 'wp_head', 'remove_font_awesome', 9999 );