substandard
adj. C1 Advanced US //səbˈstændɝd// UK //sˈʌbstændəd// sub·stan·dard
adj. not good enough to meet the usual or official standards. You use this to describe things like poor quality work or buildings that are unsafe.
adj. not meeting the required or expected standards of quality, safety, or performance. Often used in legal or technical contexts to describe work that fails to comply with minimum regulations.
The inspector found several substandard conditions in the factory.
The government shut down the restaurant after discovering substandard hygiene practices that posed a health risk to customers.
While the initial design was innovative, the final product suffered from substandard construction that led to significant structural failures within the first year of operation.
From sub- + standard.