Saving Throw

Source: D&D 5.2 SRD Rules Glossary

A saving throw — also called a save — represents an attempt to avoid or resist a threat. You normally make a saving throw only when a rule requires you to do so, but you can decide to fail the save without rolling. The result of a save is detailed in the effect that allowed it. If a target is forced to make a save and lacks the ability score used by it, the target automatically fails. See also "Playing the Game" ("D20 Tests").