Scallawag is a derogatory term used to describe a person who is considered dishonest or untrustworthy. There are several synonyms that can be used to replace the term. Some commonly used alternatives include rascal, scoundrel, villain, rogue, miscreant, knave, cad, and blackguard. These words all suggest a person who is not trustworthy and may even engage in deceitful or immoral behavior. Each has its connotations and implications, and the choice of word can depend on the context in which it is used. The use of these synonyms can add variety and nuance to your writing and make it more interesting to read.