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.
C2 [ 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).
[ after verb ] not able to be punished or damaged by something:
Journalists, he insisted, must be immune (= protected) from prosecution.