The Weakness trait reflects a single area where the character is susceptible to harm or temptation. This could be anything from an allergy like hay fever or wasp stings (not so good when fighting giant wasps!), to being weak willed and susceptible to mind control, or suffering from occasional - but paralysing - drive glitches.
The player should discuss the chosen weakness with the Gamemaster and come to an agreement over the exact nature of this Bad Trait. In most cases, when the character encounters the thing that affects them, any rolls suffer a -2 penalty. In the case of a substance like pollen or stings, the character should suffer a -2 penalty to all actions while they’re within range or exposed to its effects. For example, being stung by a wasp (not a giant Vespiform but a normal-sized one), when allergic to wasp and bee stings will result in suffering a -2 penalty to all actions for at least eight hours (or until an anti-toxin is administered), while he’s feeling weak and groggy from the poisons.
Weakness as a Major Trait is best suited for villains and aliens who need a definite exploitable weakness to give the characters a chance against them, such as weakness to acetic acid, or an extreme reaction to water or gold. Major Weaknesses actually cause injury rather than a penalty and exposure to the effective element will actually inflict 4 levels of damage, reducing their attributes (see Injuries, on pg. 85).
Weakness (Minor) – Procrastinator: The character suffers a -2 penalty to rolls when in a rushed or panicked situation.