# unsound

/ənˈsaʊnd/ (US) · /ʌnsˈaʊnd/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/unsound
Updated: 2026-05-30

## Definition

not healthy or strong. It can also describe an idea or plan that is not based on good facts or logic.

For teachers: lacking physical health or structural integrity; alternatively, based on faulty reasoning or evidence. Often used to describe financial or legal arguments that are invalid.

## Examples

- 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.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.