Probation conditions prohibiting defendant from possessing guns or illegal drugs are not vague and do not require modification. Hall was convicted of possessing cocaine base for sale and placed on probation subject to conditions. On appeal he claimed that two of the conditions—to stay away from drugs and guns—were unconstitutionally vague and should be modified to prohibit him from knowingly violating them. Held: Affirmed. Hall’s argument conflates two different concepts—vagueness of probation terms and the mens rea required to establish a violation of probation. The vagueness doctrine is concerned with whether a defendant is provided with sufficiently clear probation terms to know what is required of him. “Category conditions” that are vague may sometimes be cured by requiring that the defendant know that a particular association, place, or item is within the category prohibited, because this narrows the prohibited category in an understandable and meaningful way. However, when a prohibited category is essentially clear, there is no need to modify the condition to require that the probationer know an item is prohibited. The conditions prohibiting Hall from possessing guns or illegal drugs are sufficiently precise and do not require modification because the mens rea generally applicable to probation conditions precludes the court from finding an unwitting violation.