subparadjective
also sub-par uk/ˌsʌbˈpɑːr/usused to describe something that is below average, or below what is expected:
The economy posted sub-par annual growth of less than 2% for four straight quarters.
Does he deserve such a generous retirement package, considering the company's subpar performance?
The new chairman is attempting to revamp operations after years of subpar results at the company.