Seeing Latin "nex" as root in pernicious, I looked to see if there were other words using
that root. For instance, why not "nexious"? I found a few sites that used it, but mostly
as "handlle" in some spooky dragon sites. Then I found it in translation of a Spanish
health site:
"
Palabras clave: CARCINÓGENOS AMBIENTALES; PROMOTORES DE TUMOR; ONCÓGENOS;
VIGILANCIA INMUNOLÓGICA; SUSTANCIAS NOCIVAS.

SUMMARY

In this work we briefly show some environmental factors that may become cancerigenic in humans; among
them we can find alcohol addiction, smoking; and some especific food as well as certain in-dustrial toxics
and stress as a psychologic mechanism. These factors may modify the efficient health promotion, intended
to prevent such a terrible disease.

Key words: ENVIRONMENTAL CARCINOGENS; TUMOR-CAUSING AGENTS; ONCOGENOUS;
INMUNOLOGIC SUVEILLANCE; NEXIOUS SUBSTANCES.

But since "noxious" is from same root, I guess we don't really need "nexious". Incidentally, my
dictionary give "death" as translation of "nex".