Help! How do you actually memorize 1000+ words?

I've been trying to memorize vocabulary for the past month and feel like I'm making zero progress. Whenever I think I've memorized a bunch of words, I test myself the next day, and it's like I never saw them before. I'm an engineering student, so I'm pretty comfortable with the math section. But the verbal.... I downloaded Quizlet and have been going through word lists, but I keep mixing up definitions or just blanking out completely when I see the word in context. Has anyone else struggled with this? Like, how do you actually make vocabulary stick? I'm starting to panic because my test is in 6 weeks and I feel like I'm getting nowhere with this. Any tricks or methods that actually worked for you?