What does immunity mean?
Immunity is protection or resistance, especially against an infectious disease. It can refer to the body’s ability to resist a pathogen, often developed through vaccination or previous exposure, and it may extend to protection from toxins, allergens, or other harmful influences. The word also has an important legal sense: exemption from prosecution, liability, or punishment, such as the immunity granted to a witness who gives evidence in court. In medicine, phrases such as “immunity to disease,” “acquire immunity,” and “herd immunity” are common. In law, “legal immunity” and “immunity from prosecution” describe a legally recognized exemption. The related adjective “immune” is widely used in both areas, while “immunize” usually describes the deliberate process of creating protection.
nounImmunity is the state of being protected against a particular disease or harmful influence. In law, it can also mean exemption from prosecution, liability, or legal responsibility.
- The state of being protected, especially against a disease.
- Exemption from legal responsibility, prosecution, or liability.
"The vaccine provides immunity against the disease without exposing people to the risk of serious complications."
"Repeated exposure to the virus may build lasting immunity."
"The witness was granted immunity from prosecution in exchange for testimony."
The plural is used when referring to different protections, exemptions, or forms of immunity.
"The agreement provided the officials with broad legal immunities."
Vaccination creates immunity: a carefully trained defense that lets the body recognize a danger before it causes serious harm.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does immunity come from?
The word comes through Middle English from Latin immunitas, a noun meaning “exemption,” derived from immunis, “free from, exempt.” The same Latin root is reflected in English “immune,” and its derivatives include “immunize,” “immunization,” and “immunology.” The sense of resistance to disease developed as scientific understanding of the body’s defenses expanded during the 19th and 20th centuries.
Related word forms
How immunity is actually used
In medical contexts, immunity normally takes the preposition “to” or “against.” In legal contexts, it commonly appears with “from,” as in immunity from prosecution or liability.
Easily confused with immunity
Immunity usually means protection or exemption from a harmful influence, whereas impunity specifically means being exempt from punishment or legal consequences.