The most common and most likely answer to this crossword clue is the 14 letter word LONG-DRAWN-OUT
I've seen this crossword clue in Independent
L
O
N
G
-
D
R
A
W
N
-
O
U
T
More clues leading to the result LONG-DRAWN-OUT
Buddy explains!
The straight part
We know that "Unduly protracted" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unduly protracted = long-drawn-out.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 LONG-DRAWN-OUT mean?
LONG-DRAWN-OUT adjective- Protracted, extending for a great period of time.