Impressive set Prince offered regularly (4)
I believe the answer is:
epic
'impressive' is the definition.
(epic can mean grand or impressive)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for epic that I've seen before include "Impressively great" , "Long story telling of a hero's deeds" , "eg Beowulf" , "Guardian (body, beast)" , "Confirm the truth of" .)