I’m influenced by Massimo Pigliucci’s definition of pseudoscience. There are many good approaches, but I find Massimo’s the most satisfying.
From the interesting post:
Philosophy of Pseudoscience
“A ballpark demarcation of pseudoscience—with a lot of blanks to be filled in—is not difficult to come up with: if a theory strays from the epistemic desiderata of science by a sufficiently wide margin while being touted as scientific by its advocates, it is justifiably branded as pseudoscience.”