unsound
adj. B2 Upper Intermediate US //ənˈsaʊnd// UK //ʌnsˈaʊnd// un·sound
adj. not healthy or strong. It can also describe an idea or plan that is not based on good facts or logic.
adj. lacking physical health or structural integrity; alternatively, based on faulty reasoning or evidence. Often used to describe financial or legal arguments that are invalid.
The old bridge is unsound and needs to be replaced.
The judge ruled that the evidence was unsound because it was obtained without a proper warrant.
While the initial proposal seemed promising, a closer examination of the financial projections revealed that the entire business model was built on unsound assumptions about market growth.
From un- + sound.