If the question was to find the one word that meant 'tired', then one possibility is that the two words were sgìth and sgith. The first one has a grave accent on the ì. If you can't see the difference, it is due to Duolingo's terrible choice of typeface. Zoom in closer and you will see the difference. But even if you can see the difference here, they use a slightly different typeface here and on the questions, so it could still be that you couldn't see the difference in the question. If this is the problem then you will be completely unaware that some words have an ì, so have you seen this letter anywhere in the questions - it's quite common?