In Dungeons & Dragons (D&D) 5th Edition, the term "Immunity" denotes a creature's or object's total invulnerability to a specific type of damage or condition. When a creature has immunity to a particular damage type, such as fire or psychic, it takes no damage from attacks or effects of that type. Similarly, immunity to a condition, like charm or exhaustion, means the creature cannot be afflicted by that condition under any normal circumstances [[1†source]][[5†source]].

Immunity is a mechanic designed to emphasize the unique nature of certain creatures and their inherent defenses against specific threats. For example, a fire elemental being immune to fire damage reflects its elemental nature and origin, making it impervious to fire-based attacks. This mechanic forces players to strategize and adapt their approach when facing creatures with immunities, encouraging diversity in spell and attack selection [[5†source]].

It's crucial for players and Dungeon Masters to understand and consider immunities when planning combat encounters and adventures. Immunities can significantly impact the flow of combat, making certain attacks ineffective and challenging players to think creatively to overcome their adversaries' defenses [[2†source]][[3†source]].