I just played Codenames for the first time and was in the situation of needing to clue "Ninja" and "Czech" for the win. Ended up going with "Defenestrate". My teammates didn't end up getting it but I'm still proud of coming up with anything that could link those two words.
I gave the clue Europa and the words on the board were moon and Berlin. It wasn't that memorable of a clue, except I had to watch my wife and her friend scratch their heads and ponder out loud, "What could Europe have to do with Berlin?"