<p><strong>Noun</strong></p><ul><li>Informal, plural coot·ies:<ul><li>a louse, especially one affecting humans, as the body louse, head louse, or pubic louse.</li><li>a child's term for an imaginary germ or disease that one can catch by touching a person who is disliked or socially avoided: The girls at camp thought the boys had cooties.</li></ul></li></ul>