随分is an adverb meaning considerably, quite, extremely, or surprisingly. It is used to emphasize that something has reached a degree that exceeds one's expectations. In some contexts, it can also imply that something is reprehensible or too much.
That is how Fuguro works. It brings 随分 back for review right before you forget it, each time a little later, until it sticks for good. You hear it spoken aloud, and you meet it again in stories you can already read. The first five levels are free.