The most common and most likely answer to this crossword clue is the 5 plus 2 plus 5 letter word LYING IN STATE
I've seen this crossword clue in The Guardian
L
Y
I
N
G
I
N
S
T
A
T
E
Buddy explains!
The straight part
We know that "a great honour for a body" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a great honour for a body = lying in state.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.