Smite

Smite is a category of unique weapon attacks that, unlike regular attacks, which generally only cost an  Action, additionally expend spell slots (and often a  Bonus Action) to activate. Though requiring a spell slot, they do not consume the spell slot (nor bonus action, when applicable) on a miss. As they are considered weapon attacks, they can be used with  Extra Attack and can be used multiple times per turn. The damage they deal is also affected by critical hits.

List of smite actions

•  Banishing Smite 
•  Branding Smite 
•  Blinding Smite
•  Divine Smite
•  Searing Smite 
•  Staggering Smite 
•  Thunderous Smite
•  Wrathful Smite 
•  Lunar Smite (NPC-exclusive)

Divine Smite

Notably, Divine Smite functions differently from the other smites. Despite consuming spell slots, Divine Smite is not a spell and does not interact with any effect or ability that only works with spells. Examples include  Counterspell,  Vivacious Cloak, or  Tempestuous Magic.

Unlike other smite spells, Divine Smite can be configured to trigger automatically on hit inside the Reactions menu with  Divine Smite (reaction). The reaction is split into two options per spell slot level unlocked, one for normal hits called Divine Smite and one for critical hits called Divine Smite: Critical Hit. This means that with level 2 spell slots, there will be four Divine Smite reactions (two per level) that can be configured separately. By default, the Divine Smite: Critical Hit reactions are set to auto-confirm, and the normal Divine Smite reactions are disabled.

Using Divine Smite as a reaction has a number of advantages. It allows Divine Smite to be combined with any melee weapon attack (that is not  Divine Smite itself), such as off-hand attacks, weapon actions like  Cleave, or special attacks like  Great Weapon Master: Bonus Attack. It can even trigger when using another smite spell. Using Divine Smite directly through the action is less flexible and is equivalent to using the reaction on a basic attack.

When used as a reaction, the only additional resource consumed is the selected level of spell slot. Even though it is configured in the Reactions menu, Divine Smite never consumes a  Reaction resource.

Other smites

Other smites cannot be used as reactions and must be used manually; however, Divine Smite can be triggered as a reaction when using other smite spells, allowing for two different smites on a single attack. Other smites also count as proper spells for the purpose of features that interact with them, like  Ring of Elemental Infusion or  Empowered Evocation, and can even be affected by Counterspell.