The word "invulnerability" means being completely immune or resistant to harm or damage. It refers to the state of being unable to be hurt or injured. Full definition
«Rage Attack» moves provide a powerful buff and a short period of invulnerability for the cost of a Spirit Gauge, mixing up combat and adding flow to the battle mechanics. (esperino.com)
The most potent weapon is the elusive pick - axe which grants temporary invulnerability as Toad and Toadette manically smash through walls and enemies. (thesixthaxis.com)
Another ability that was certainly abused was the «Armor lock», wherein players with low health would enter a state of invulnerability for approximately five seconds, leaving the attacking player dumbfounded. (cubedgamers.com)