"Predatory journals" is a term attributed to a librarian, Jeffrey Beall, who began publishing a list of "predatory open-access publishers" in 2008. Beall wanted to name publishers who took advantage of the move towards open access and who used unscrupulous methods to lure scholarly articles for thier publications. Beall stopped publishing his list in early 2017, having experienced such blowback from publishers he named and from some other controversial views that he held.
Publishers do not have to use the guise of being "open access" to be classified as predatory. Nevertheless, there are steps that a scholar can take when looking for a journal in which to publish.