Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
immunised is an adjective meaning "having been rendered unsusceptible to a disease". It carries one recorded sense.
having been rendered unsusceptible to a disease
Definitions, synonyms and semantic relations for immunised come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.