Vocabulary Trainer

Learning vocabulary can be a horror, but with the right tool, the horror becomes pure pleasure. Fear no more, learn with Vocabulary Trainer, a modern, reliable, highly customizable and extraordinarily feature-rich solution that makes learning vocabulary easier, with support for sometimes extraordinary but extremely important aspects, available for Windows, MacOS and Linux.

And... it is 100% free and open-source.

A non-exhaustive list of the most important features

Organize them: Vocabulary can be divided into lessons.
Synonyms and Antonyms: Specify and learn synonyms and antonyms of a word. This is an often missing feature, which is highly valued in Vocabulary Trainer.
Variety of learning modes: Find your own learning style that suits you best. Choose from:
- Flashcards: Memorize vocabulary super fast by flipping flashcards.
- Write: The best solution for learning the exact spelling of a word, and it's quite similar to an exam too.
- Multiple Choice: Choose the correct answer from 4 options.
- Synonyms and Antonyms: Focus on learning synonyms and antonyms only.
- Vocabulary List: Do you prefer just looking at a list of words with their term and definition as well as optionally their synonyms and antonyms? Then this is your choice.
To know, or not to know, that's the question: Words you define correctly or incorrectly are automatically tracked, so that you know how much you still need to learn. This also leads us to the next important point...
Progressive assistance: Let the application ask you words, you don't know well, more frequently, so you can focus on the important things. This option can be turned on and off as you like, as with many other aspects in the application.
Freedom with settings: Customize each learning mode individually with a wide range of options that allow you to adjust many aspects of learning with Vocabulary Trainer to your needs.
Intelligent examination: The application offers a number of settings that control how strictly your written definition should be compared with the actual definition of a term.
Beautiful and responsive design: The design of Vocabulary Trainer's user interface comes from the heart. Enjoy the beauty, while simplicity has not been omitted.

and more...

Privacy

Privacy is a big deal at Vocabulary Trainer, bigger than in any other app or website you know. Why? Because Vocabulary Trainer collects absolutely no data from the user and requires no internet connection for any of the features. It is a 100% "local" application without any hidden or visible data transfers. No server, no problems. Only your lessons with the vocabulary are stored locally, but are not visible to anyone except the user of the device on which they're saved. Hooray for learning incognito!