Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. dērĕlictus, a, um, Part., from derelinquo.
* 2. dērĕlictus, ūs, m. [derelinquo], an abandoning; trop., a neglecting, neglect: aliquid habere derelictui, Gell. 4, 12, 2.