Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. mistus (mix-), a, um, Part., from misceo.
2. mistus (mix-), ūs (only in the abl. sing.), m. [misceo], a mixing, mingling (post-Aug.): seminis mistu, Col. 6, 37, 7 dub.