likely to cause damage or injury; harmful; noxious.
Origin of nocuous
1625–35; < Latin nocuus harmful, injurious, equivalent to noc(ēre) to harm + -uus deverbal adj. suffix; see -ous
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
rare harmful; noxious
Word Origin for nocuous
C17: from Latin nocuus, from nocēre to hurt
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
1630s, "noxious, harmful," from Latin nocuus "harmful," from stem of nocere "to hurt, injure, harm" (see innocuous).
Online Etymology Dictionary, © 2010 Douglas Harper