The most common and most likely answer to this crossword clue is the 2 plus 3 plus 2 plus 3 plus 4 letter word ON TOP OF THE WORD
I've seen this crossword clue in The Daily Telegraph
O
N
T
O
P
O
F
T
H
E
W
O
R
D
Buddy explains!
The straight part
We know that "Elated,/as Hillary once was?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case elated,/as hillary once was? = on top of the word.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.