The crossword solution for the term BACKSEAT is REAR, which is a four-letter word. The term 'backseat' is often used to refer to someone who is not in control of a situation or who is not taking an active role. It can also be used to describe someone who is not taking responsibility for their actions. In this context, the word 'REAR' is a fitting solution as it implies a position of being behind or subordinate.