The term 'Fill with Optimism' can be summarized by two crossword solutions: ELATE (5 letters) and UPLIFT (6 letters). ELATE is a verb meaning to make someone very happy or excited, while UPLIFT is a verb meaning to raise someone's spirits or make them feel more positive. Both words are used to describe the act of filling someone with optimism, which is the feeling of hope and confidence that good things will happen in the future.