twisted

FUNCTIONS:

add_filter('site_url',  'wplogin_filter', 10, 3);

function wplogin_filter( $url, $path, $orig_scheme )
{
 $old  = array( "/(wp-login\.php)/");
 $new  = array( "access");
 return preg_replace( $old, $new, $url, 1);
}


//your new codes
add_action('init','my_redirect');

function my_redirect(){
    global $pagenow;
    if( 'wp-login.php' == $pagenow) {
        wp_safe_redirect('404.php');
       //Don't forget to exit() becuse wp_redirect doesn't exti automatically
       exit();
   }
 }



HTACCESS:
RewriteRule ^access$ wp-login.php [NC,L]