Sufficient space is a term used to describe the amount of ROOM needed for a particular purpose. It can refer to physical space, such as a ROOM, or it can refer to a figurative space, such as the amount of time or resources available. In this case, the crossword solution for the term 'sufficient space' is 'ROOM, ' which is a four-letter word. ROOM is a physical space that can be used for a variety of purposes, from living and working to storage and recreation.