The most common and most likely answer to this crossword clue is the 12 letter word EXHILARATING
I've seen this crossword clue in The Daily Telegraph
E
X
H
I
L
A
R
A
T
I
N
G
Buddy explains!
The straight part
We know that "Raising the spirits of" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case raising the spirits of = exhilarating.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.
What does EXHILARATING mean?
EXHILARATING verb- To cheer, to cheer up, to gladden, to make happy.
- To excite, to thrill.
- Refreshingly thrilling.