Vocabulary doesn't stick — words are 'in one ear and out the other' even right after you look them up

Summary

A defining, intensely frustrating pattern for vocabulary learners: even learners who find grammar and pattern-matching easy watch new words vanish immediately after encountering and looking them up. The word is recognized for a moment and forgotten by the next encounter, so comprehension never converts into durable mastery no matter how often the word is seen. Existing tools do not close this loop: dictionary extensions translate and move on, flashcard apps require manual deck building, and both pull the learner out of the reading that would give the word context. The learner is left 'adjusting methods' by hand with no system that captures words in context while reading and re-surfaces them so they actually stick without breaking flow. This is the core unsolved pain of the topic and it directly drives self-doubt and the feeling of learning nothing despite constant effort.