Sit by Definition 1 of 3Pro Tip 1/3Moral Dilemma Indicates a choice to avoid action when it might be expected; often seen as negative. She couldn't just sit by while the argument escalated. Pro Tip 2/3Bystander Effect Used to describe someone who observes an event but doesn't engage or intervene. During the robbery, everyone sat by, too shocked to react. Pro Tip 3/3Call to Action Often used in motivational or inspirational contexts to encourage proactive behavior. You can't sit by when injustice is happening.