Learning a language can feel like climbing a mountain sometimes. For every word you learn there are certainly a thousand more. I know that I don’t know every word in the English language so it is unlikely I shall ever learn every word in the Portuguese language!
Whilst fluency is always the goal of the language learner, we need to keep an eye on the basics of language: learning those words that we know we will need to use at some time or another. Of all the hundreds of thousands of words in any given language, we only tend to use a certain percentage of them. Some people have a greater vocabulary than others but a lot of the time we use basic staples. For example I know what the words ‘rhetoric’ ‘lapel’ and ‘usurp’ mean but they are not part of my everyday language. Much the same goes for ‘antidisestablishmentarianism’ which I think I can safely say will never get a look-in in a conversation (and this will be the only time I ever write it!). Words that we know the meaning of but never use are called ‘passive’ words by linguists.
When faced with that very high mountain, one of the best things you can do for yourself is to relax and accept you are never going to learn every word there is in your target language. Once you have done this, you can then rest in the knowledge that it is positively ok not to learn every single word you come across.