The most common and most likely answer to this crossword clue is the 3 plus 8 plus 4 plus 7 letter word ONE THOUSAND FIVE HUNDRED
I've seen this crossword clue in The Times
O
N
E
T
H
O
U
S
A
N
D
F
I
V
E
H
U
N
D
R
E
D
Buddy explains!
The straight part
We know that "MD/MD" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case md/md = one thousand five hundred.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.