The term resist meant that a player, mob, or NPC was not, or only to a lesser extent, affected by a spell or elementalattack. Full resists completely negated the effect and had the same effect as Immune. Partial resists only reduced the damage received by a percentage; these could only occur with non-binary spells.
There were two sources for spell resists. Firstly, the level difference between the caster and their target determined the spell hit chance. A spell which missed its target resulted in a full resist, whereas partial resists could not occur. Spell hit rating decreased the chance of getting a resist due to this difference. Secondly, Resistances increased the chance to resist a spell. They could cause both full and partial resists, and could be overcome with spell penetration (and, limited to binary spells, spell hit rating). A full resist due to level difference could not be distinguished from a full resist due to resistances.
There were also some negative spell hit effects in the game, such as the [Balance of Power] and [Unbreakable Will]. The former decreased the total spell hit chance of the attacker, whereas the latter only affected the spell hit chance of specific abilities.
Resists were the magical counterpart of Miss, Dodge, and Parry. Even though the Armor attribute and Defenseskill generally affect the ability to mitigate physical damage, they were not considered resistances. However, there are some border cases; for example, the Hunter's [Arcane Shot] could be partially resisted, but a full resist is shown as a miss in the combat log. Some spells, such as [Chaos Bolt], could not be resisted.