Overt and Covert errors are categorized as translation assessments that focus on functional match of lexical items. This study investigates functional equivalence (overt error) in translating idioms in the American fantasy film Maleficent. This study aims to explore the common problems in translating idioms because of non-equivalence and to describe the overt errors. The study used a mixed (qualitative and quantitative) research design, with random sampling technique used for data collection. The data of this study comprised twenty idioms from the film Maleficent, with the objective to examine the problem of non-equivalence in translating idioms. Baker's Functional Target Language Equivalence theory of translation and House' Model of Translation Quality Assessment were used to figure out overt errors. The study found out eight common translation problems including complexity of source-language words; difference in expressive meaning; source-language concept not lexicalized in the target language; source and target languages make different distinctions in meaning; target language lacks superordinate, cultural-specific concepts and specific terms. In addition, the study also discovered some overt errors in translating idioms due to breach of language system; change in meaning; cultural filtering, and distortion of meaning. This study was confined to only those idioms which have common non-equivalence problems; hence generalization of findings is not emphasized.