olemus
(1a) tervishoius:
organismi vastupanuvõime haigustele
Wiktionary:
1. (medicine) protective resistance against disease

(1b) bioloogias:
hulkraksete organismide vastupanuvõime
kahjulikele mikroorganismidele
Wiktionary:
2.a resistance to a specific thing
Superbugs are bacteria that develop an immunity to antibiotics.

(1c) tehnikas:
elektroonikalülituse elektromagnetiline häiringutundetus
= the ability of a device to keep functioning when exposed to electromagnetic radiation

ülevaateid
https://en.wikipedia.org/wiki/Immunity_(medical)