sensitising vs immunization

sensitising and immunization both are nouns.

Word	Noun	Adjective	Verb	Adverb
sensitising	Yes	Yes	No	No
immunization	Yes	No	No	No

As nouns, immunization is a hypernym of sensitising; that is, immunization is a word with a broader meaning than sensitising:

sensitising: rendering an organism sensitive to a serum by a series of injections
immunization: the act of making immune (especially by inoculation)

Other hypernyms of sensitising include immunisation.

sensitising (noun)	immunization (noun)
rendering an organism sensitive to a serum by a series of injections	the act of making immune (especially by inoculation)

sensitising (adjective)	immunization (adjective)
making susceptible or sensitive to either physical or emotional stimuli