"Dost double duty" means that something serves two purposes or performs two functions simultaneously. There are several synonyms for this phrase, including "multi-functional," "versatile," and "dual-purpose." Other words that can be used to describe something that does double duty include "two-in-one," "all-in-one," and "flexible." The phrase is often used when referring to objects or products that have more than one use, such as a piece of furniture that can be used as both a table and a chair. It is also used to describe people who take on multiple roles or responsibilities, such as a teacher who is also a coach or a parent who is also a caregiver.