›protected against a particular disease by particular substances in the blood: Most people who've had chickenpox once are immune to it for the rest of their lives.He seems to be immune to colds - he just never gets them.Immunology and vaccinationC2[after verb]not affected or upset by a particular type of behaviour or emotion: The press had criticized her so often that in the end she had become immune (to it).Not showing or feeling emotionsControlling emotions›[after verb]not able to be punished or damaged by something: Journalists, he insisted, must be immune (= protected)from prosecution.Safe and secure