瘋狂背單字 - TOEIC TOEFL 全民英檢 is an Android app developed by CT Tseng, designed for English language learners. The app offers more than 10,000 TOEIC, TOEFL, and GEPT vocabulary words. The app uses a pop-up card format to display the vocabulary words, which appear and disappear on the phone screen at regular intervals. This allows users to learn English vocabulary words while using their phones without any disturbance.

The app provides several features, such as floating pop-up cards for GEPT and TOEIC vocabulary words, a toolbar with commonly used functions like pronunciation, word translation, and word storage, a personal vocabulary library, and a self-test feature. Users can also customize the app's pop-up card appearance, set the appearance time, and switch between Yahoo and Google dictionaries.