How to find a word in large word list (vocabulary) with descent memory consumption and look-up time?

Question

Problem

[Here follows a description of what the app should do under which constrains]

I want a data-structure that searches if a string e

Answer 1

This sounds like an ideal use for a bloom filter. If you're willing to allow the risk of something being falsely considered a word, you can condense your wordlist into an amount of memory as small or as large as you're willing to make it.