"Be a sponger" is a derogatory phrase that refers to someone who relies on other people to provide for them, without making any effort themselves. There are several synonyms that can be used to describe someone who behaves in this way. Some of the most common synonyms include mooch, freeloader, leech, parasite, and scrounger. These words all have similar meanings, and they are often used interchangeably in conversations and written content. When used in a negative context, they can be quite demeaning, as they imply that the person is lazy and unwilling to take responsibility for their own needs and desires.