A character’s trait is a dominant characteristic based on his attributes. It provides an ability or quality related to either his highest or lowest attribute. Traits include things like rugged, massive, alcoholic, inspiring, and so on. If someone were to describe your character, this is the first word they’d use—“Ben? You mean that suave spy?”
Choose either your highest or lowest attribute (both will give you an advantage; choosing the lowest doesn’t give you a disadvantage—for example, a low WIL allows you to choose “alcoholic,” which gives you a bonus SOAK score when intoxicated). Choose a corresponding trait (or roll for it if you prefer a little randomness).
Your trait forms part of your descriptor and should be noted on your character sheet. For example: