The degree of ambiguity in the term suicide attempt was examined among 14 expert suicidologists, and 59 general mental health clinicians who either did or did not receive a standard definition of the term. The participants judged whether each of ten vignettes of actual adolescent self-harm behaviors was a suicide attempt. Low levels of agreement were found within each group, although agreement was better for the most and least serious cases. Possible explanations were examined, including how professionals weight suicidal intent and medical lethality in their suicide attempt decisions, and the use of a “fuzzy,” natural language conceptualization of suicide attempts was proposed.