Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
com-mingo, minxi, minctum, 3, v. a., to pollute, defile: lectum potus (by vomiting), * Hor. S. 1, 3, 90: suavia comminxit spurcā salivā tuā, Cat. 78, 8; cf. id. 99, 10: commictum caenum, as a term of reproach, for a paltry, dirty fellow: commictum caeno stercilinium publicum, Plaut. Pers. 3, 3, 3.