From Bulbapedia, the community-driven Pokémon encyclopedia.
Example of titles displaying in battle
A title or special title is a phrase that can display after a Pokémon's name when it is sent out in battle. Titles were introduced in Generation VIII.
If a Pokémon has any mark or Ribbon, the title corresponding to it can be freely toggled on and off. Only one title can be active at a time. In Link Battles, any titles on the opposing team's Pokémon will display as well.