title_body: Borrowing from conlangs into natural languages Are there known cases of borrowing of words from a constructed language into a natural language?
  
  Words constructed arbitrarily in a natural language don't count here. For example, the Estonian word relv "weapon, firearm" coined in the 20th century (probably influenced by English revolver) wouldn't count.
upvoted_answer: The verb "to grok", having been coined by Robert Heinlein for his Novel Stranger in a Strange Land has gained significant popularity and is used with the same meaning as in the original language. 
  
  I am however not sure whether this meets the criteria of coming from a constructed language: To my knowledge the martians' language is clearly stated to be a full fledged language inside universe of the book, but "to grok" is one of the few (if not only) word to be given explicitly and there does not seem to be a full-fledged grammar or lexicon anywhere. 
  
  See also [1]; [2]