serious Synonyms - page 3

arduous austere awful bookish burdensome burro businesslike classical cogitative committed complicated concentrative consequential considerable esoteric eventful jeopardous key maggiore major material mean meditative menacing momentous museful nasty operose owlish parlous pensive peracute intense humorless exigent extreme fateful frowning gravely graver gravity great grim grinding hard harder hazardous heartrending heavy historic