<p><strong>Verb (used without object):</strong></p><ul><li>to expel air from the lungs suddenly with a harsh noise, often involuntarily.</li><li>(of an internal-combustion engine) to make a similar noise as a result of the failure of one or more cylinders to fire in sequence.</li><li>to make a similar sound, as a machine gun firing in spurts.</li></ul><p><strong>Verb (used with object):</strong></p><ul><li>to expel by coughing (usually followed by up or out): to cough up phlegm.</li></ul><p><strong>Noun:</strong></p><ul><li>the act or sound of coughing.</li><li>an illness characterized by frequent coughing.</li><li>a sound similar to a cough, a machine gun, or an engine firing improperly.</li></ul><p><strong>Verb phrase (Slang):</strong></p><ul><li>to relinquish, especially reluctantly; contribute; give.</li><li>to blurt out; state, as by way of making a confession: After several hours of vigorous questioning by the police, he finally coughed up the information.</li></ul>