The most common and most likely answer to this crossword clue is the 11 letter word CACOPHONOUS
I've seen this crossword clue in The Times
C
A
C
O
P
H
O
N
O
U
S
Buddy explains!
The straight part
We know that "Harsh" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case harsh = cacophonous.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 CACOPHONOUS mean?
CACOPHONOUS adjective- Containing, consisting of, or producing harsh, unpleasant or discordant sounds.