Dictionary.com
definitions

ingravescent

adjective
  1. rare (esp of a disease) becoming more severe
Derived Formsingravescence, noun

Word Origin for ingravescent

C19: from Latin ingravescere to become heavier, from gravescere to grow heavy, from gravis heavy
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
ingravescent in Medicine

ingravescent

[ĭn′gră-vĕs′ənt]
adj.
  1. Becoming increasingly severe.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.