While addressing issues of prejudice and exclusion is crucial for helping adult second language (L2) learners acquire and critique socio-interactional norms of their pluralistic communities, there is still a lack of work examining how teachers can problematize prejudiced talk when it arises in the classroom. Within the detail-oriented frameworks of conversation analysis and membership categorization analysis, this study examines teacher practices for problematizing students' hearably prejudiced, stereotypical, or exclusionary talk--that is, students' possible -isms. Drawing on data from 55 hours of video-recorded English L2 classes in the United States, I explore three problematizing responses to possible -isms: (i) introducing complexities, (ii) offering counter examples, and (iii) treating -isms as absurd. While introducing complexities neutralizes students' hearable -isms as somehow inadequate, the latter two practices treat the -isms as entirely inaccurate through illustrated and invited corrections. The analysis reveals these practices to be finely attuned to the institutional goals and features of the adult L2 classroom, allowing teachers to incorporate a critical perspective and delicately problematize possible -isms without threatening solidarity with their diverse adult learners.