Cannot dequeue script in child theme

In functions.php of my parent theme, I have these

function karuna_scripts() {

wp_enqueue_script( 'karuna-functions', get_template_directory_uri() . 
'/assets/js/functions.js', array( 'jquery' ), '20160531', true );

}

add_action( 'wp_enqueue_scripts', 'karuna_scripts' );

I am trying to Dequeue 'karuna-functions' in a child theme

// BEGIN DEQUEUE PARENT ACTION

function remove_parentstickyfunctions() {
    wp_dequeue_script('karuna-functions');
}

add_action('wp_enqueue_scripts','remove_parentstickyfunctions');

// END DEQUEUE PARENT ACTION

But I am still getting the sticky menu functionality which I believe is loaded from /assets/js/functions.js of the parent theme.

How do I remove the sticky menu functionality in the child theme?