\Cough\ (k?f), v. i. [imp. & p. p. {Coughed} (k?ft); p.
pr. & vb. n. {Coughing}.] [Cf. D. kuchen, MHG. k?chen to
breathe, G. keuchen to pant, and E. chincough, the first part
of which is prob. akin to cough; cf. also E. choke.]
To expel air, or obstructing or irritating matter, from the
lungs or air passages, in a noisy and violent manner.

\Cough\, v. t.
1. To expel from the lungs or air passages by coughing; --
   followed by up; as, to cough up phlegm.
2. To bring to a specified state by coughing; as, he coughed
   himself hoarse.
{To cough down}, to silence or put down (an objectionable
   speaker) by simulated coughing.

\Cough\, n. [Cg. D. kuch. See {Cough}, v. i. ]
1. A sudden, noisy, and violent expulsion of air from the
   chest, caused by irritation in the air passages, or by the
   reflex action of nervous or gastric disorder, etc.
2. The more or less frequent repetition of coughing,
   constituting a symptom of disease.
{Stomach cough}, {Ear cough}, cough due to irritation in the
   stomach or ear.