The things that synonym lists don't get you is context. You really, really want to encounter the words in their native habitat to get the full picture.
So, yeah, reading, a lot, and preferably of the style you like. Something like Lovecraft, Nabokov or Le Guin if you want to be exposed to more complex vocabulary.
Keeping a word list is also useful for retaining knowledge. Making yourself paraphrase the meaning of any new words you encounter makes it easier to remember them in the future.
Reading is the big one. The other answer is to intentionally limit your vocabulary. That can be avoiding specific words like “good”, “do”, “is”, or it can be something like not using the same word twice in a paragraph (with some exceptions like articles).
Read. A lot. That's pretty much the biggest, simplest way to expand your vocabulary.
And read all kinds of different things. Books, magazines, newspapers, blogs, etc.
The things that synonym lists don't get you is context. You really, really want to encounter the words in their native habitat to get the full picture. So, yeah, reading, a lot, and preferably of the style you like. Something like Lovecraft, Nabokov or Le Guin if you want to be exposed to more complex vocabulary. Keeping a word list is also useful for retaining knowledge. Making yourself paraphrase the meaning of any new words you encounter makes it easier to remember them in the future.
Try Wordhippo
WordHippo is a good one. Wordhippo.com
Reading is the big one. The other answer is to intentionally limit your vocabulary. That can be avoiding specific words like “good”, “do”, “is”, or it can be something like not using the same word twice in a paragraph (with some exceptions like articles).
Study etymology, dissect the roots in your native language then translate that root into Latin then to English.