ETYMOLOGY
from Latin morbus (disease) + -ulent
EXAMPLE
“… they should apply such medicines as are suitable, and in such a Proportion as is most proper to assist Nature in the Discharging of the Malignant and Morbulent Matter; but never to clog and hinder its Motions by too many and useless doses. …”
From: The History of the Works of the Learned,
Or, An Impartial Account of Books Lately Printed in all parts of Europe.
Done by Several Hands, Volume VI
The Works of the Learned, for February 1704
Lexicophilia 