The term 'further down' can be represented by four different crossword solutions: DEEPER (6 letters), LOWER (5 letters), bluer (5 letters), and mopier (6 letters). DEEPER means to go to a greater depth, LOWER means to go to a LOWER level, bluer means to become more blue in color, and mopier means to become wetter or more moist. All of these words refer to the idea of going further down, either literally or figuratively.