This paper investigates how, and to what extent the flexibility and robustness of a partial parser can be utilized to automatically extend existing semantic lexicons. Our work is based on the observation that members of a semantic group are often surrounded by other members of the same group in text. Given a few category members we collect surrounding contexts and try to identify other words that also belong to the same group. Large quantities of partially parsed corpora is an important ingredient for the enrichment and further development of the semantic resources.