The word "working" can be used in many different contexts, and as such, there are many different synonyms that can be used to replace it. Some possible synonyms for "working" include "employed," "operating," "functioning," "busy," "productive," "effective," "efficient," "active," and "engaged." Depending on the specific meaning that one is trying to convey, different synonyms may be more appropriate. For example, "employed" might be a good synonym to use when referring to someone who is currently working at a job, whereas "engaged" might be more useful when talking about someone who is actively involved in a project or task.