Learning new words in a foreign language means learning new labels for the same reality: it doesn't matter what you call a bird, it
is still a bird. It doesn't matter what word you use for the act of making love, what counts is the object, the idea, the action, the feeling. And that has to be uppermost in our minds when we learn
new labels for known realities.
In other words, Greek ὁ ἵππος τρέχει and English the horse is running both express the same reality, namely a real horse really running.
It is not enough to think:
ὁ ἵππος means "the horse", because it doesn't, not really. It means the animal we call horse, the Greek call hippos and the Japanese call uma.
What is wrong with learning ἵππος horse and horse ἵππος. Nothing really, except that your whole approach to language learning shifts from learning to use the language itself to learning to translate, which are 2 totally different skills altogether.
The proof. No matter how well you know your lists of words, when faced with having to use them spontaneously you're lost. Can't remember a word. Millions of people learn foreign languages, hardly any can speak, or even understand those languages they've been learning, sometimes for years.
And what do you do when you've got to write a few sentences? Prepare them in English and translate them into foreign. Hardly a good reference for your language proficiency. And it has nothing whatsoever to do with intelligence, or gift for languages, but with approach to language study.
Most important read everything out loud - to fix words and structures through eyes AND ears. And read, read, re-read and listen to recordings if possible.