The word you're likely looking for is "mild" or "moderate".
If you're describing something that is not severe, you can use one of these words instead:
* Mild: A mild illness, a mild reaction
* Moderate: Moderate pain, moderate exercise
* Slight: A slight injury, a slight inconvenience
You can also use other words depending on the context, such as:
* Benign: A benign tumor
* Minor: A minor injury
* Non-serious: A non-serious condition
* Simple: A simple problem
* Easy: An easy task
If you can provide more context, I can help you choose the most appropriate word.