Optimistic means having a positive outlook or expecting good outcomes. It is the belief that things will turn out well in the future.
For example, someone who is optimistic might believe that they will succeed in their goals or that a difficult situation will improve. They have hope and confidence in a positive outcome even when things are challenging. Optimism is the opposite of pessimism, which is having a negative or gloomy outlook.
Very Simple Definition:
Optimistic means thinking positively or believing that good things will happen.
For example, if you think you will do well on a test and feel happy about it, then you are being optimistic. Another example is when you believe that the sun will come out after a rainy day and it makes you feel hopeful.