Pernicious
ahd-5
adjective.
Tending to cause death or serious injury; deadly.
adjective.
Causing great harm; destructive.
The Century Dictionary and Cyclopedia
Quick.
Having the property of destroying or being injurious; hurtful; destructive.
Wicked; malicious; evil-hearted.
the GNU version of the Collaborative International Dictionary of English
adjective.
Quick; swift (to burn).
adjective.
Having the quality of injuring or killing; destructive; very mischievous; baleful; malicious; wicked.
Wiktionary, Creative Commons Attribution/Share-Alike License
adjective.
Causing much
harm
in a
subtle
way.
adjective.
Causing
death
or
injury
;
deadly
.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adjective.
exceedingly harmful
adjective.
working or spreading in a hidden and usually injurious way
Word Usage
"It is time to undertake the reform of what I call a pernicious prejudice."