"Hook, line, and sinker" is a popular phrase that refers to being completely taken in or fooled by something. It originated from fishing terminology as hooks, lines, and sinkers are essential equipment for catching fish. However, several synonyms can be used instead of this phrase, such as "completely deceived," "taken in," "gullible," "trapped," and "fooled." Other common expressions that convey a similar meaning are "swallowed it whole," "fell for it," "bought it," "sucked in," and "fell hook, line, and sinker." Regardless of the saying, they all have to do with succumbing wholeheartedly to deception, manipulation, or falsehood.