The term 'WORKING WELL' can be summarized by the crossword solution 'EFFICIENT', which is a nine-letter word. Efficiency is a measure of how well resources are used to achieve a desired outcome. It is often used to describe the performance of a system, such as a business or organization, in terms of how much output is produced with a given amount of input. In other words, efficiency is a measure of how much work is done with the least amount of effort.