The victim in "victimless" is inherently controversial. Laws are generally intended to protect people, so a criminal act is likely to have some victim, however abstract. There are four distinct possible meanings for "victimless."
First, consensual crimes with (arguably) no material harm (such as
sodomy laws in the
United States, prior to
Lawrence v. Texas).
Second, crimes in which the damage caused is overwhelmingly borne by the perpetrator, such as suicide or drug use. As the perpetrator has chosen to suffer the effects of these crimes, they are not a "victim" in the normal sense.
Third, crimes in which the cost is borne by an abstract society or group of people, without a clear, direct victim. This could be applied to driving without auto insurance (where mandated by law).
Fourth are crimes against non-"victims", non-human entities, like governments. These are victimless not because no harm occurs, but because the recipient of the harm is not properly considered a "victim." This is thus a question of the definition of victim, rather than a question of the effects of the crime.