Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† astĭcus, a, um, adj., = ἀστικός, of or pertaining to the city, city-: ludi, games celebrated in the city in honor of Bacchus, Suet. Calig. 20 (al. iselastici; v. iselasticus).