The term BEST-CASE SCENARIO can be broken down into two words: 'best-case' and 'SCENARIO'. The term 'best-case' refers to the most favorable outcome that could possibly occur, while a 'SCENARIO' is a hypothetical situation. Therefore, the term BEST-CASE SCENARIO refers to a hypothetical situation with the most favorable outcome. The crossword solution for this term is IDEAL, which means 'the best of all possible worlds'. In other words, IDEAL is the perfect word to describe a BEST-CASE SCENARIO.