The word "questionable" means something that is uncertain or questionable. It suggests that there are doubts or suspicions surrounding it. Full definition
Yet they remain exempt from many of the performance and safety standards we put on public schools — even after studies showing lackluster performance and news reports of questionable uses of public funds. (host.madison.com)
That is bound to allow schools to set prices higher than they otherwise would and offer degrees with questionable value in the labor market. (brookings.edu)
But more than 70 percent of the scientists stated they would be less likely to engage in questionable practices now that they've become aware of the problems they cause. (sciencenews.org)