I think I can help you out with that, the answer to 'be furious' in the NYT crossword is probably 'seethe' or 'rage', but the one that fits most crosswords is 'seethe', it's a pretty common answer for that clue, have you tried that, if not, you can also try 'irate' or 'fume', but 'seethe' is usually the one that works, let me know if that helps you out.