As Helen Slater is a proper noun representing an individual's name, it is difficult to provide direct antonyms for this term. However, we could consider the term as a member of a group or category such as actors, celebrities or performers. In this context, we could suggest some antonyms for these categories, such as non-celebrities, amateur actors or non-performers. Another approach could be to consider the qualities or characteristics that Helen Slater may possess, such as talent, fame or beauty, and identify their antonyms. Antonyms for talent could be incompetence, ineptitude, or clumsiness, whereas for fame, it could be anonymity, obscurity or unknown identity.