Prosperous, or preposterous (4)
I believe the answer is:
rich
I believe this is a double definition.
'prosperous' is the first definition.
(similar in meaning)
'preposterous' is the second definition.
(rich can mean outrageous or unbelievable)
(Other definitions for rich that I've seen before include "Abundant" , "Having many possessions" , "elaborately decorated" , "Possessing material wealth" , "Full-bodied" .)