Smite

Smite is a category of unique weapon attacks that, unlike normal attacks which generally only cost an  Action, additionally expend Spell Slots (and often a  Bonus Action) in order to activate. Though requiring a spell slot to initially activate, they do not consume the spell slot (nor bonus action, when applicable) on a miss. As they are considered weapon attacks they can trigger and be used with  Extra Attack, and in the case of  Divine Smite can be used multiple times per turn. The damage they deal is also subject to modification caused by a critical hit.

List of Smite abilities

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

Notably, Divine Smite functions slightly differently from the other smites. Here are the key differences.

Divine Smite

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 one reaction for normal hits called Divine Smite and one for critical hits called Divine Smite: Critical Hit for each spell slot level unlocked. 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 offhand attacks, weapon actions like  Cleave, or special attacks like  Great Weapon Master: Bonus Attack. It can even trigger when using a Smite spell like  Thunderous Smite. Using Divine Smite directly through the action is less flexible and is equivalent to triggering the reaction on a basic attack.

When triggered through 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 the  Reaction resource.

Other Smites

Other smites cannot be triggered 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 in a single attack. Other smites also count as proper spells for the purposes of features like Ring of Elemental Infusion or  Empowered Evocation, and will interact with effects such as these, including the possibility of being affected by Counterspell.