When someone is in charge of something, they are responsible for overseeing, supervising, or managing it. There are several different words that can be used as synonyms for "in charge (of)". These include "responsible for", "in control of", "leading", "heading", "managing", and "commanding". Each of these words carries a slightly different connotation, but all convey the idea that someone has authority over a particular task or project. It is important to use the right word depending on the context of the situation, but in general, all of these words can be interchangeable with "in charge (of)".