Collins COBUILD Advanced Learner's English Dictionary - unsound

1. If a conclusion or method is unsound, it is based on ideas that are wrong. The thinking is good-hearted, but muddled and fundamentally unsound... The national tests were educationally unsound. ? sound ADJ: usu v-link ADJ 2. If something or someone is unsound, they are unreliable. No sensible person would put his money in a bank he knew to be unsound. = unreliable ADJ 3. If you say that something is unsound in some way, you mean that it is damaging in that way or to the thing mentioned. The project is environmentally unsound... A diet extremely low in calories can also be a diet that is nutritionally unsound. ? sound ADJ: usu v-link ADJ, usu adv ADJ 4. If a building or other structure is unsound, it is in poor condition and is likely to collapse. The church was structurally unsound. ADJ: usu v-link ADJ