If you describe an accusation, rumour, or report as baseless, you mean that it is not true and is not based on facts. The charges against her are baseless. baseless allegations of drug taking. = unfounded. not based on facts or good reasons - used to show disapproval = unfounded baseless rumours/charges/accusations
without a basis in reason or fact; "baseless gossip"; "the allegations proved groundless"; "idle fears"; "unfounded suspicions"; "unwarranted jealousy"