Weariness is a temporary feeling of low energy and tiredness. Most people feel weariness after a long day of work. Marathons, babysitting small children, standardized tests, and getting old can also cause weariness.
When you're weary, you're tired. Put a –ness at the end of the word to make a noun, and viola! weariness is the condition of feeling tired or fatigued. In fact, the familiar French loan word fatigue means “weariness.” Physical work (like helping someone move) or mental work (like reading a difficult book) can make you experience weariness. If a busy schedule is making you feel a general sense of weariness, it’s time for a vacation.