title_body: Methods to avoid similarity in lexicons
upvoted_answer: A modern approach to this problem is to generate the words automatically according to some formula describing allowed words. You can filter out words that are too close to already generated ones, but usually the randomness used by a computer program will be sufficient.
  
  There are well-known examples of Conlangs with computer generated vocabulary. Loglan and Lojban used some vocabulary lists from natural languages as input for their vocabulary generating algorithm.