Show posts from two or more custom taxonomy terms

You need to combine two tax queries with and AND relation:

$args = array(
    'posts_per_page' => 10,  // Number of posts per page
    'post_type' => 'classifieds',   // Custom Post Type like Movies
    'tax_query' => array(
        'relation' => 'AND'
        array(
            'taxonomy' => 'classifieds_tags',   //Custom Taxonomy Name like Genre
            'field' => 'slug',
            'terms' => array(
                'books' //Tags or Categories like Drama or Comedy
            )
        ),
        array(
            'taxonomy' => 'classifieds_tags',   //Custom Taxonomy Name like Genre
            'field' => 'slug',
            'terms' => array(
                'houses'
            )
        ),
    )
);