OBJECTIVES The objective of this study was to assess the translatability of “frustrated,” a term commonly used to describe a range of emotions in Clinical Outcomes Assessments (COA). “Frustrated” includes many constructs, such as “discouragement,” “anger” and “upset.” Previous studies have shown that terms including multiple constructs in English, such as “bother,” are not sufficiently translatable across all languages.  METHODS Back-translations of questionnaires containing the word “frustrated” were analyzed to assess the translatability of the term. The following related constructs were also included in analysis: “discouraged,” “angered,” “disappointed” and “upset.” Data collection forms resulting from cognitive debriefing were also analyzed to determine subjects’ interpretation of “frustrated” as translated in other languages. RESULTS “Frustrated” proved to be very problematic for 13 out of the 24 languages in this study, most notably for Eastern European, Indian and Asian languages. For example, “frustrated” was translated as “indignant” in Greek, “disillusioned” in Hungarian, “irritated” in Japanese and “discouraged” in Korean. Out of 245 subjects, 13% took issue with “frustrated,” indicating that it was not understood or not appropriate for their languages. Analyses of related constructs showed that “discouraged” and “angered” were best suited for use, as these terms were translated with no issues in all 12 languages available for analysis. “Upset” was found to be equally problematic, and thus rejected as a recommended construct.  CONCLUSIONS “Frustrated” is not recommended for use in COAs intended for international data pooling. Similar to the findings of previous studies, more specific terms, such as “discouraged” and “angered,” translate with greater conceptual equivalency. Therefore, when seeking to measure the various concepts associated with the term “frustrated,” measuring more specific constructs independently using separate questionnaire items is recommended.