<p><strong>Adjective</strong></p><ul><li>physically filthy; disgustingly unclean: a nasty pigsty of a room.</li><li>offensive to taste or smell; nauseating: This ointment is really nasty—couldn't they make it smell less vile?</li><li>ugly, catty, bitchy, malevolent, malicious, mean, repellent, repulsive, sickening.</li><li>offensive; objectionable: a nasty habit.</li><li>vicious, spiteful, or unkind: a nasty dog; a nasty rumor.</li><li>bad or hard to deal with; dangerous; serious: a nasty accident.</li><li>very unpleasant or disagreeable: nasty weather.</li><li>morally filthy; obscene; indecent: a nasty word.</li></ul><p><strong>Noun</strong></p><ul><li>plural nasties.</li><li>Informal: a nasty person or thing.</li></ul>