From the Rulebook:
Class Abilities that functions all of the time without activation being required.
Includes such things as Immunity and the ability to use extra equipment.
Traits are denoted with a (T) and are always non-magical in nature.
Traits may not be removed by any means and persist after respawn.
Immunities granted by Traits persist after death.
Traits are not enchantments, and do not count towards enchantment limits or count for the purposes of Attuned, Essence Graft or similar Magic and Abilities.
Note: Some Traits mimic other Magic or Abilities, but these Traits are still always on and ignore any Incantation or Materials requirement listed.