Directional suffixes are a type of word ending that indicate the direction of an action or movement. The crossword solution for the term 'directional suffixes' is ERNS, which stands for the suffixes -erns, -ers, -erse, and -erst. These suffixes are used to indicate motion or direction in a particular way, such as towards, away from, around, or through. For example, the word 'walkers' has the suffix -ers, indicating that the action of walking is directed towards something.