The most common and most likely answer to this crossword clue is the 8 letter word CICERONE
C
I
C
E
R
O
N
E
Buddy explains!

The straight part
We know that "guide" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case guide = cicerone.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 CICERONE mean?
CICERONE noun- A guide who shows people around tourist sights.
- To show (somebody) the sights, acting as a tourist guide.