Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† trĭbăs, ădis, f., = τριβάς (rubbing), a woman who practises lewdness with women, Phaedr. 4, 14, 3; Mart. 1, 91 tit.; 7, 67, 1; 7, 70, 1; Cael. Aur. Tard. 4, 9.