The word "man-child" is a noun that refers to an adult male who behaves in a childish or immature way. It combines the words "man" (an adult male) and "child" (a young person).
A man-child is a grown man who acts like a kid. This can mean he avoids responsibilities, has childish interests, or is dependent on others, like parents or partners, to take care of him.
You can use "man-child" when you want to describe a man who is not acting his age, especially when he should be taking on adult responsibilities. It is often used in a critical or negative way.
In more advanced discussions, "man-child" can be used in social or psychological contexts to describe behaviors that prevent personal growth or maturity in men. It can also be a point of discussion in gender studies about societal expectations of masculinity.
Overall, "man-child" is a descriptive term that points out when an adult male is not living up to the expectations of maturity and responsibility.