The definition of junk science is inaccurate or false studies, data and analysis which is used to create a biased opinion or to push a political agenda.
An example of junk science is a study funded by the tobacco industry that finds second hand smoke isn't harmful.
(uncountable, pejorative) Assertions that have the appearance, but not the actuality, of scientific support.
His testimony was worse than science fiction: it was junk science.
(countable, pejorative) A cluster of assertions, publications, and experts that have the appearance, but not the actuality, of a scientific specialty.