Kills WordPress search query

query-killer.php

<?php
add_filter( 'posts_where', 'x_kill_search_query', 10, 2 );

function x_kill_search_query( $where, $query ) {
	if ( ! is_admin() && $query->is_main_query() ) {
		// this is a self-removing callback
		remove_filter( current_filter(), __FUNCTION__, 10 );

		if ( $query->is_search() ) // only kill the main query
			$where = ' AND 1=0 /* Query killed */';
	}
	return $where;
}