Stepdad is a term used to refer to a man who becomes a father figure to a child through marriage to the child's mother. There are several synonyms for the word stepdad, which can be used interchangeably depending on the context. Some of the synonyms for stepdad include stepfather, bonus dad, father figure, second dad, and dad-in-law. These synonyms can be used to refer to a father figure who loves, cares, and supports the child just like a biological father would. It is important to note that regardless of the term used, the relationship between a child and their stepfather is a special one, which deserves love and respect.