The term 'Tough to Endure' can be summarized by two crossword solutions: 'TRYING' (6 letters) and 'HARSH' (5 letters). This phrase implies that something is difficult to go through, and that it requires a great amount of effort and strength. It can also suggest that the situation is unpleasant or even painful. The words 'TRYING' and 'HARSH' both emphasize the difficulty of the experience and the potential for suffering.