<p><strong>Noun</strong></p><ul><li>A rough cabin; shanty.</li><li>Informal: radio shack.</li></ul><p><strong>Verb Phrase</strong></p><ul><li>Slang: to live together as spouses without being legally married.</li><li>To have illicit sexual relations.</li><li>To live in a shack: He's shacked up in the mountains.</li></ul>