Co-dependent is an adjective used to describe a relationship where one person excessively relies on another person for emotional or psychological support. There are several synonyms for this word. One of them is reliant, which means someone who depends heavily on others for their emotional or psychological wellbeing. Another synonym for co-dependent is interdependent, which refers to a mutually beneficial relationship where both parties rely on each other. Needy is another adjective that can be used to describe a co-dependent relationship where one person is excessively dependent on the other. Lastly, symbiotic can be used to describe a co-dependent relationship where both parties benefit from each other's reliance.