Sure, its 5 letters
But voltage I've got an idea. To promote educated guessing in this game it should be limited to approx. 15 guesses per word. Just like in Mastermind if there are too many wrong guesses you lose the game, so if you go 15 words out and no one has it correct, the person who made up the word can go again. This game was your idea so feel free to say no but I feel that it is a nice solution to your problem with long lists of random words.