When W.M. Wheeler came up with the term superorganism, he was thinking that ant colonies were organisms, plan and simple—not a particular kind of organism. Is there an diagnostic attribute universal to organisms that we could look for in defining superorganisms, too? Yes: the component cells of all organisms share a tight identification to the whole, giving them a sense of self and non-self. Other than the gametes and embryos that form new individuals under conditions specific to a species (each new individual with a novel identity), no part of an organism has the option to set up shop alone or defect to another individual. That’s true whether the organism is as simple as the Volvox shown below, or as complex as a person.
If pushed sufficiently hard, any definition outside those for mathematical terms and other abstractions will break down. Show me a car, and I might show you a pile of junk that once functioned as a car (and maybe in a mechanic's mind it still is). Show her a star, and an astronomer points to a mass of convergent superheated dust. The hallmark of a good definition is not entirely that it tidily delimits a set of X's, but that it also necessarily causes problems (breaks down) when things get conceptually interesting about X, as when the biological species concept presents difficulties for organisms undergoing the kinds of change Mayr (1963) considers pivotal to the generation of new species, or when a parasitic plant starts to resemble a mutualist.
So the question is this: If we use cooperation / conflict criterion to define superorganisms, is it possible to select a particular cutoff point within the continuum of possibilities that is conceptually exciting, rather than arbitrary? That would be a robust definition. We should also ask, can such a definition be aligned with the intended comparison to organisms? If not, it should be applied to a different word than "superorganism."