Trait

A trait is an attribute — an origin or a class — attached to each TFT champion, shown beside their portrait. Fielding enough champions that share a trait activates a bonus for your whole board, and many traits have multiple breakpoints that get stronger as you add more units.

Every champion has two or more traits, so picking units is really about which trait combinations you want to switch on. Building around active traits is the core of every comp, and the bonuses they provide are commonly called synergies. Traits are reworked with each new set, so the strongest combinations change regularly.