[im-yuh-nahyz, ih-myoo-nahyz]
verb (used with object), im·mu·nized, im·mu·niz·ing.
  1. to make immune.
  2. to render harmless or ineffective; neutralize.
  3. Law. to grant (a witness) immunity.
Also especially British, im·mu·nise.

Origin of immunize

First recorded in 1890–95; immune + -ize
Related formsim·mu·niz·er, nounhy·per·im·mu·nize, verb (used with object), hy·per·im·mu·nized, hy·per·im·mu·niz·ing.non·im·mu·nized, adjectiveo·ver·im·mu·nize, verb (used with object), o·ver·im·mu·nized, o·ver·im·mu·niz·ing.un·im·mu·nized, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for unimmunized



  1. to make immune, esp by inoculation
Derived Formsimmunization or immunisation, nounimmunizer or immuniser, noun
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

Word Origin and History for unimmunized



1889, from immune + -ize. Related: Immunized; immunizing.

Online Etymology Dictionary, © 2010 Douglas Harper

unimmunized in Medicine


  1. To render immune.
  2. To produce immunity in, as by inoculation.
Related formsim′mu•ni•zation (-nĭ-zāshən) n.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.