The phrase "serious disadvantage" means having a significant or important disadvantage that can negatively impact or harm someone's situation or ability to succeed. Full definition
When it comes to fitness training, women are at serious disadvantage. (liftingrevolution.com)
Schools can not reverse serious disadvantage unless they have resources, funding and expertise provided by the local authority. (politics.co.uk)
Just remember that guaranteed issue life insurance policies are also going to have some pretty serious disadvantages to them as well. (termlife2go.com)