hideous /ˈhɪd.i.əs/ adjective4 •Extremely or shockingly ugly.I’m sorry to break it to you, but your dress looks truly hideous. •Having a very unpleasant or frightening sound.He started up, growling at first, but finding his leg broken, fell down again; and then got upon three legs, and gave the most hideous roar that ever I heard. — 1719 •Hateful; shocking.Sure, you have some hideous matter to deliver. — 1601 •Morally offensive; shocking; detestable.when the wind is shrieking, and the men are yelling, and every plank thunders with trampling feet right over Jonah’s head; in all this raging tumult, Jonah sleeps his hideous sleep. — 1851 formsmore hideous · most hideous