corroborate
The definition for corroborate is "To support with evidence." Used in a sentence: "Unless you can corroborate your story, it will not be admissible in court," the attorney told his client.
ecstatic
The definition for ecstatic is "Overwhelmingly emotional." Used in a sentence: They were ecstatic when their team won the championship game in the last second.
extant
The definition for extant is "Currently existing." Used in a sentence: Some consider Clint Eastwood the greatest extant American director.
onset
The definition for onset is "Beginning." Used in a sentence: Crocuses bloom at the onset of spring, sometimes even before the snow melts.
trove
The definition for trove is "Valuable collection." Used in a sentence: Walter's trove of vintage baseball cards was worth thousands of dollars.