The above question was closed as primarily opinion-based. In fact, a great deal of research has been conducted into this very question. This research is reviewed by Paul Nation (probably the most well-known name in second language vocabulary acquisition) in his book Learning Vocabulary in Another Language (Cambridge University Press, 2001). On page 298 Nation summarizes:
There is evidence that the presence of a sentence context can help with making the word form-word meaning association (Laufer and Shmueli, 1997), but there is also an enormous amount of evidence that shows that even without a sentence context large numbers of words can be learned in a short time and retained for a very long time.
I think this information might be useful for the asker of the question and other viewers of the page.