Source : Webster's Revised Unabridged Dictionary (1913)

Chin cough \Chin" cough"\ [For chink cough; cf. As. cincung long
   laughter, Scot. kink a violent fit of coughing, akin to MHG.
   k[=i]chen to pant. Cf. {Kinknaust}, {Cough}.]
   Whooping cough.