The crossword solution for the term 'Totally Impractical' is MAD, which is a three letter word. MAD stands for 'Mutually Assured Destruction', which is a military doctrine that was developed during the Cold War. This doctrine states that if two opposing sides have enough nuclear weapons to destroy each other, then neither side will attack the other, as it would result in mutual destruction. This doctrine was seen as totally impractical, as it relied on both sides having enough nuclear weapons to destroy each other, and thus was seen as a dangerous way of maintaining peace.