1. A close friend or companion: This is the most common informal use. It implies a close bond and a sense of loyalty and support between two people.
Example: "My best friend is my sidekick. We do everything together."
2. A person who assists someone else in their activities: This meaning is often used in a less serious context than "sidekick" in a superhero comic book or movie. It can describe someone who helps out with tasks or errands, even if they aren't always involved in the main activity.
Example: "My little brother is my sidekick for grocery shopping. He helps carry the bags."
3. A person who is subservient or inferior to another: This meaning is less common, but it can be used to suggest that someone is always following another person's lead and doing what they are told.
Example: "He's just the boss's sidekick. He doesn't have any real authority."
It's important to consider the context of the conversation to understand which meaning is intended.